Pomological traits, chemical composition, and antioxidant activity of white mulberry genotypes (Morus alba)
Subject Areas : Plant Physiology
Behzad Babazadeh Darjazi
1
*
,
Mozhgan Farzami Sepehr
2
1 - Department of Horticulture, Roudehen Branch, Islamic Azad University, Roudehen, Iran
2 - Department of Biology, Faculty of Agriculture, Islamic Azad University, Saveh Branch, Saveh, Iran
Keywords: genotypes, Morus alba, sugars, total acid, white mulberry,
Abstract :
Given its nutritive value, mulberry is consumed both fresh and in various processed forms. This study aimed to investigate the pomological traits, chemical composition, and antioxidant activity of the fruits of white mulberry genotypes. Folin-Ciocalteau colorimetric method and aluminum chloride colorimetric method, respectively, were used to measure the content of total flavonoids and total phenols. Antioxidant properties were evaluated using a DPPH radical scavenging assay. Using HPLC glucose and fructose were found and analyzed. In all samples glucose was the dominant sugar with the highest concentration. The level of fructose (4.28 g/100 g) and glucose (5.06 g/100 g) in fruits of genotype 2 and the amount of total acid (0.21%) in the fruits of genotype 3 were higher than other genotypes. Compared to genotype 2, the antioxidant capacity of genotype 3 was noticeably higher (22%), as measured by the DPPH assay. The study demonstrated that genotypes had a significant impact on the chemical properties of mulberry fruits. A strong positive correlation was found between fructose and pH. Findings revealed useful information about chemical composition of white mulberry genotypes, which can be utilized in food industry and as valuable genetic resources for breeding programs.
Abd EL-Malak, G., F. B. EL-Kasas and S. Youssef .2010. Evaluation of some mulberry species and their suitability for processing jams. Journal of Food and Dairy Sciences, 1(11): 697-707.
Akin, M., S. P. Eyduran, S. Ercisli, V. Kapchina-Toteva and E. Eyduran. 2016. Phytochemical profiles of wild blackberries, black and white mulberries from southern Bulgaria. Biotechnology & Biotechnological Equipment, 30(5): 899-906.
Aljane, F., N. Sdiri, R. Laamari, S. Ochatt and A. Ferchichi. 2016. Morphological, phytochemical and antioxidant characteristics of white (Morus alba L.), red (Morus rubra L.) and black (Morus nigra L.) mulberry fruits grown in arid regions of Tunisia. Journal of New Sciences, 35:1940-1947.
Amin, W. A. and R. Attia . 2003. Characterization of the Egyptian mulberry (Tut) fruits for preparing processed products and natural colours. Journal of Food and Dairy Sciences, 28(3): 1895-1909.
Bajpai, P. K., A. R. Warghat, P. Dhar, A. Kant, R. B. Srivastava and T. Stobdan .2014. Variability and relationship of fruit color and sampling location with antioxidant capacities and bioactive content in Morus alba L. fruit from trans-Himalaya, India. Lwt-food science and technology, 59(2): 981-988.
Balik, A., M. K. Gecer and R. Aslantas . 2019. Diversity of biochemical content in fruits of some indigenous mulberry genotypes." Turkish Journal of Agriculture and Forestry, 43(1): 28-35.
Chen, X., K. Yuan and H. Liu. 2010. Phenolic contents and antioxidant activities in ethanol extracts of Citrus reticulata Blanco cv. Ougan fruit. Journal of Food, Agriculture & Environment, 8(2): 150-155.
Çöçen, E., H. Pınar, A. Uzun, M. Yaman, A. Aslan and O. T. Altun .2018. Phenological, Pomological and Technological Characteristics of Seedless White Mulberry in Mulberry Genetic Resources of Turkey. Turkish Journal of Agriculture-Food Science and Technology, 6(10): 1317-1321.
Du, Q.-Z., J.-f. Zheng and Y. Xu .2008. Composition of anthocyanins in mulberry and their antioxidant activity. Journal of Food Composition and Analysis, 21(5): 390-395.
Elhami, R. A. and S. Estiri .2009. Evaluation of physicochemical properties and vinegar production process of two varieties of white berries in Sabzevar. Innovation in Food Science and Technology (Food Science and Technology), 1 (1), 25-40.
Ercisli, S. and E. Orhan .2007. "Chemical composition of white (Morus alba), red (Morus rubra) and black (Morus nigra) mulberry fruits." Food chemistry, 103(4): 1380-1384.
Ercisli, S. and E. Orhan .2008. Some physico-chemical characteristics of blackmulberry (Morus nigra L.) genotypes from Northeast Anatolia region of Turkey. Scientia Horticulturae, 116(1): 41-46.
Eyduran, S. P., S. Ercisli, M. Akin, O. Beyhan, M. K. Geçer, E. Eyduran and Y. Erturk. 2015. Organic acids, sugars, vitamin C, antioxidant capacity, and phenolic compounds in fruits of white (Morus alba L.) and black (Morus nigra L.) mulberry genotypes. Journal of Applied Botany and Food Quality, 88. 134 - 138
Farhangi, H., M. Ajilian, M. Saeidi and G. H. Khodaei .2014. Medicinal fruits in holy Quran. International Journal of Pediatrics 2(3.2): 89-102
Gao, X., Q. Hou and Z. Ma .2020. Differences of sugar components in Different Mulberry Cultivars during its ripening. IOP Conference Series: Earth and Environmental Science, IOP Publishing.
Gecer, M. K., M. Akin, M. Gundogdu, S. P. Eyduran, S. Ercisli and E. Eyduran. 2016. Organic acids, sugars, phenolic compounds, and some horticultural characteristics of black and white mulberry accessions from Eastern Anatolia. Canadian Journal of Plant Science, 96(1): 27-33.
Gozlekci, S., H. Uzun and A. Yegin .2014. Some physico-chemical characteristics of mulberry (Morus alba, Morus laevigata, Morus nigra) species grown in western Turkey. XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes. VI International Symposium on Human Health Effects of Fruits and Vegetables. pp: 191-197.
Gundogdu, M., I. Canan, M. K. Gecer, T. Kan and S. Ercisli .2017. Phenolic compounds, bioactive content and antioxidant capacity of the fruits of mulberry (Morus spp.) germplasm in Turkey. Folia Horticulturae, 29(2): 251-262.
Gundogdu, M., F. Muradoglu, R. G. Sensoy and H. Yilmaz .2011. Determination of fruit chemical properties of Morus nigra L., Morus alba L. and Morus rubra L. by HPLC. Scientia horticulturae, 132: 37-41.
Gundogdu, M., M. Tuncturk, S. Berk, N. Sekeroglu and S. Gezici .2018. Antioxidant capacity and bioactive contents of mulberry species from Eastern Anatolia region of Turkey. Indian Journal of Pharmaceutical Education and Research, 52(4): 96-101
Gungor, N. and M. Sengul .2008. Antioxidant activity, total phenolic content and selected physicochemical properties of white mulberry (Morus alba L.) fruits. International Journal of Food Properties, 11(1): 44-52.
Hassanpour, H. and S. Firooz Barandoozi .2020. Investigation of Physicochemical Characteristics and Fruit Color of Some White Mulberry (Morus alba) Genotypes in West Azerbaijan Province of Iran. Isfahan University of Technology-Journal of Crop Production and Processing, 9(4): 145-158.
Hepsağ, F., Ö. Gölge and İ. Hayoğlu. 2016. Effect of genotypes on chemical and physical properties of mulberry. Hacettepe Journal of Biology and Chemistry, 44(3): 225-231.
Huang, H.-P., T.-T. Ou and C.-J. Wang. 2013. Mulberry (Sang Shèn Zǐ) and its bioactive compounds, the chemoprevention effects and molecular mechanisms in vitro and in vivo. Journal of traditional and complementary medicine, 3(1): 7-15.
Imran, M., H. Khan, M. Shah, R. Khan and F. Khan. 2010. Chemical composition and antioxidant activity of certain Morus species. Journal of Zhejiang University Science B, 11: 973-980.
Ionica, M.-E., V. Nour and I. Trandafir. 2017. Bioactive compounds and antioxidant capacity of some Morus species. South-western Journal of Horticulture, Biology and Environment, 8: 79-88.
Janick, J. 2003. Horticultural Reviews, Volume 29: Wild apple and fruit trees of central Asia, John Wiley & Sons.
Kumar D., B.P. Singh and P. Kumar. 2004. An overview of the factors affecting sugar content of potatoes. Annals of Applied Biology, 145:247-256.
Lee, J.-H., J.-B. Whang, N.-R. Youn, S.-Y. Lee, H.-J. Lee, Y.-J. Kim and K.-H. Koh. 2009. Antioxidant and oxygen radical scavenging capacities of the extracts of pear cactus, mulberry and Korean black raspberry fruits. Preventive Nutrition and Food Science, 14(3): 188-194.
Mahmood, T., F. Anwar, M. Abbas, M. C. Boyce and N. Saari 2012. Compositional variation in sugars and organic acids at different maturity stages in selected small fruits from Pakistan. International journal of molecular sciences, 13(2): 1380-1392.
Makhoul, G., H. Mahfoud and H. Baroudi 2017. Some chemical characteristics of white (Morus alba L) and black (Morus nigra L) mulberry phenotypes in Tartus Syria. SSRG International Journal of Agriculture & Environmental Science, 4(2): 53-62.
Muthiah, P., M. Umamaheswari and K. Asokkumar . 2012. In vitro antioxidant activities of leaves, fruits and peel extracts of Citrus. International Journal of Phytopharmacy, 2(1): 13-20.
Negro, C., A. Aprile, L. De Bellis and A. Miceli. 2019. Nutraceutical properties of mulberries grown in southern Italy (Apulia). Antioxidants, 8(7): 223.
Paunović, S. M., P. Mašković and M. Milinković. 2020. Determination of primary metabolites, vitamins and minerals in black mulberry (Morus nigra) berries depending on altitude. Erwerbs-Obstbau, 62(3): 355-360.
Radojković, M. M., Z. P. Zeković, S. S. Vidović, D. D. Kočar and P. Z. Mašković. 2012. Free radical scavenging activity and total phenolic and flavonoid contents of mulberry (Morus spp. L., Moraceae) extracts. Hemijska industrija, 66(4): 547-552.
Şengul, A. Y., T. Şengul, Ş. Çelik, G. Şengül, A. Daş, H. Inci and A. Ş. Bengu.2021. The effect of dried white mulberry (Morus alba) pulp supplementation in diets of laying quail. Revista MVZ Córdoba, 26(1): 4-14.
Shahidi F. 2012. Dried Fruits: Phytochemicals and Health Effects, John Wiley & Sons, New York.
Singh, S. and M. Choudhary 2012. Production Technology of Fruit Crops in Wasteland, Scientific Publishers.
Skender, A., M. Kurtović, S. Ercisli and D. Bećirspahić. 2019. Some physicochemical characteristics of black and white mulberry genotypes from Bosnia and Herzegovina. Genetika, 51(3): 1089-1101.
Vaughan, J. and C. Geissler. 2009. The new Oxford book of food plants, OUP Oxford.
Vega, E. N., A. K. Molina, C. Pereira, M. I. Dias, S. A. Heleno, P. Rodrigues, I. P. Fernandes, M. F. Barreiro, D. Stojković and M. Soković. 2021. Anthocyanin’s from Rubus fruticosus L. and Morus nigra L. applied as food colorants: A natural alternative. Plants, 10(6): 1181.
Yilmaz, K., Y. Zengin, S. Ercisli, M. Demirtas, T. Kan and A. Nazli. 2012. Morphological diversity on fruit characteristics among some selected mulberry genotypes from Turkey., 22(1): 211-214.
1405
Behzad Babazadeh Darjazi1* and Mozhgan Farzamisepehr2
1. Department of Horticulture, Islamic Azad University, Roudehen Branch, Roudehen, Iran
2. Department of Biology, Faculty of Agriculture, Islamic Azad University, Saveh Branch, Saveh, Iran
________________________________________________________________________________
Abstract
Given its nutritive value, mulberry is consumed both fresh and in various processed forms. This study aimed to investigate the pomological traits, chemical composition, and antioxidant activity of the fruits of white mulberry genotypes. Folin-Ciocalteau colorimetric method and aluminum chloride colorimetric method, respectively, were used to measure the content of total flavonoids and total phenols. Antioxidant properties were evaluated using a DPPH radical scavenging assay. Using HPLC glucose and fructose were found and analyzed. In all samples glucose was the dominant sugar with the highest concentration. The level of fructose (4.28 g/100 g) and glucose (5.06 g/100 g) in fruits of genotype 2 and the amount of total acid (0.21%) in the fruits of genotype 3 were higher than other genotypes. Compared to genotype 2, the antioxidant capacity of genotype 3 was noticeably higher (22%), as measured by the DPPH assay. The study demonstrated that genotypes had a significant impact on the chemical properties of mulberry fruits. A strong positive correlation was found between fructose and pH. Findings revealed useful information about chemical composition of white mulberry genotypes, which can be utilized in food industry and as valuable genetic resources for breeding programs.
Keywords: genotypes, Morus alba, sugars, total acid, white mulberry
Babazadeh, B., M. Farzamissepehr. 2023. 'Pomological traits, chemical composition, and antioxidant activity of white mulberry genotypes (Morus alba)'. Iranian Journal of Plant Physiology 14(2), 4935- 4944.
|
____________________________________ * Corresponding Author E-mail Address: babazadeh.b@gmail.com Received: September, 2023 Accepted: March, 2024
|
Mulberry fruit can be eaten as a pastry, utilized for tarts, pies, and jams, squeezed and made into a beverage and syrup, and handled into wine (Vaughan and Geissler, 2009). Additionally, waste vinegar and bekmes are made from mulberry fruits (Janick, 2003). The fruit of the mulberry tree is used to treat anemia, weakness, dizziness, fatigue, and nausea. It can help get rid of constipation, improve digestion, increase gastric juice secretion, and treat chronic digestive tract diseases. In traditional Chinese medicine, the fruit has a lot of significance because it is used to treat hair graying before it starts. In Chinese medicine, it is also used to treat diabetes and constipation and also to purify the blood (Singh and Choudhary, 2012).
According to Şengul et al. (2021), fresh mulberry contains 7.8-9.0% carbohydrates, 0.5-1.4% protein, 0.3-0.5% fatty acids (linoleic, stearic, and oleic acids in seeds), 1.1-1.8% free acid (primarily malic acid), 0.9-1.3% fiber, 0.8-1.0% ash, and 85-88% moisture. Additionally, mulberry fruits contain a lot of phenolic compounds, such as carotenoids, flavonoids, and anthocyanins (Huang et al., 2013). The antioxidant power of the fruit is due to the presence of ROS scavengers such as phenolic compounds (Lee et al., 2009). Ripe fruits are rich in anthocyanins, which are excellent antioxidants with stronger free radical scavenging effects than vitamin C (Du et al., 2008).
The mulberry fruit is a great source of vitamin C which is a powerful natural antioxidant. In addition, it contains sufficient amounts of vitamin A and some B vitamins (Paunovic et al., 2020). B vitamins help the body break down carbohydrates, proteins, and fats by acting as co-factors (Farhangi et al., 2014). Sugars are the basic raw material for the synthesis of other nutrients like pigments, amino acids, vitamins, and aromatic substances, as well as the primary component of fruit quality and flavor (Gao et al., 2020). According to Eyduran et al. (2015), the fructose content in all mulberry types is between 4.05 and 7.70 g / 100g and the glucose content of all types of mulberry fruit ranges from 5.33 to 9.43 g / 100 g. The fruit sugar content can vary significantly depending on genotype, environment, and other factors (Gundogdu et al., 2017).
Organic acids of fruit are one of the key factors in fruit flavor and have a significant impact on flavor and human health. Organic acids like malic, citric, and tartaric acids were highlighted in a number of studies that are important for the prevention and elimination of kidney stones (Eyduran et al., 2015). Malic acid (123-218 mg/g) is the most common organic acid in mulberry, followed by citric acid (21-41 mg/g) (Ercisli and Orhan, 2008). Organic acids also have a significant impact on the organoleptic properties of fruits and can help preserve their nutritional value. Depending on their nature, organic acids are frequently used in food industry as antioxidants, acidulating agents, or preservatives (Vega et al., 2021).
The physicochemical characteristics of white mulberry genotypes have been the subject of numerous studies (Hassanpour and Firooz Barandoozi, 2020). There have been global reports of some studies on the sugar variation of white mulberry genotypes. Eyeduran et al. (2015) indicated that genotypes directly affected the amount of fructose and glucose in mulberry. In addition, they discovered that white mulberry genotypes had fructose and glucose levels of approximately 4.05 to 7.70 and 5.33 to 9.43 g/100 g, respectively. Gundogdu, et al. (2018) suggested that genotypes affect the amount of fructose and glucose in mulberry fruits. In addition, they mentioned that the genotypes of white mulberry contained between 4.65 and 8.13 g of glucose and 3.53 and 6.16 g of fructose per 100 grams, respectively. Individual sugars from white mulberry genotypes grown in Iran have not been reported. Therefore, the objective of this study was to investigate the pomological traits, chemical composition and antioxidant activity in the fruits of white mulberry genotypes.
Material and Methods
Chemicals and standards
Standards of Sigma-Aldrich Chemical Co. for fructose, glucose, gallic acid, 2, 2-diphenyl-1-picrylhydrazyl (DPPH), acetonitrile, methanol, and Folin-Ciocaltaeu were used in the study. The sodium carbonate, rutin, and sodium hydroxide used in the study came from Merck (Darmstadt, Germany).
Plant materials
During May to June 2016, ripe fruit samples of white mulberry genotypes (Morus alba) were collected from the orchards of Roudehen in Tehran, Iran. The experiment had three replications with three genotypes and a completely random design. For each tree, about 1 kg of fruit were picked and transferred to the research facility in separate plastic bags. Sample bags were stored in a refrigerator at 5 ℃ for future analyses.
Juice analysis
Fruit juice was extracted with a juicer. The individual sugars were determined using HPLC method. Before analysis, all samples were centrifuged at 15,000 g for 20 minutes at 4 ℃ to remove any pulp or fine particles that might clog the column. Using a pH meter or phenolphthalein as an indicator, samples of the juice were titrated with 0.1 N sodium hydroxide (NaOH) to measure total titratable acid. A Jenway digital pH meter (model: 3510) was used to precisely measure and record the juice's pH values. Total soluble solids were measured using a refractometer (Kruss, Germany). Titration with potassium iodide was used for the measurement of ascorbic acid
Sugars
A Platin blue system (Knauer, Berlin, Germany), with a binary pump and a Refractive Index (RI) detector, were used for the HPLC analysis. A Shodex Asahipak NH2P-50 4E column (250×4.6 mm) was used for the separation. The elution was performed isocratically using a mobile phase of acetonitrile/water (75/25, v/v) at a flow rate of 1.0 ml/min. The column temperature was maintained at 25 ℃, and the injection volume for each sample was 10 μl. The retention times of unknown peaks and standards were compared in order to identify sugar peaks. Fructose and glucose were dissolved in distilled deionized water separately, to make standard sugar solutions. A standard calibration curve was built up by injecting three times at three different concentrations. Using a standard calibration curve and peak areas, the concentrations of individual sugars were measured. The result was expressed as a gram compound per 100 grams (g/100g).
Physical traits
Fifty fruits from each tree were taken randomly to determine the physical characteristics. After drying in an oven at 80 degrees Celsius, the moisture content was determined. To measure the ash, the weighed fruits were put in a furnace at 560 ℃. A scale was used to measure the fresh and dry weights. Using a caliper, the fruit's length and diameter were measured. The ratio of length to diameter was used to determine the shape of the fruit.
Phenolic compounds
The method of Chen et al. (2010) for extracting phenolic compounds from fruits was used with slight changes. In a 200 ml spherical flask, 20 ml of methanol were added to approximately 2 grams of dried fruit powder. The flask was sealed tightly with paraffin film and placed in an ultrasonic bath for 20 minutes. The ultrasonic cleaning bath (Fisatom Scientific-FS14H) with the following dimensions was used for the extraction: 24 × 14 × 10 cm. The operating frequency was 40 KHz, and the total power was 90 W. The temperature was kept at about 40 ℃ for 20 minutes. Methanol was used to dilute the aqueous extract to 40 mm after it was passed through a 0.45 mm filter paper. The tops of the vials were sealed and stored at 4 ℃ in the refrigerator for subsequent analysis.
Total flavonoids
Aluminum chloride colorimetric assay was used to estimate total flavonoid contents. About 1 ml of diluted extract was added to 0.5 ml of a solution of NaNO2 (5% w/v), followed by 0.5 ml of 10% AlCl₃ solution after 5 min, and the resulting solution was homogenized. Six minutes later, 5 ml of NaOH 1 M solution was added, and the resulting solution was mixed. The absorbance was measured at 415 nm after five minutes. Rutin was used as the standard, and the results were expressed as mg of rutin equivalents per g dry weight. About 16.2 mg of rutin was dissolved in 100 ml of 70% ethanol, shaken, and used to create the standard curve at concentrations of 0, 75, 100, and 125 mg/l (Chen et al., 2010)
Total phenols
Table 1 Statistical analysis of variation in juice compositions and fruit physical traits of white mulberry genotypes
The mean is the average of traits applied with three replicates. SD = standard deviation. Results of analysis of variance: NS = not significant, the * significant difference at P ≤ 0.05, ** significant difference at P ≤ 0.01.Any two means within a row not followed by the same letter are significantly different at P ≤ 0.01 or P ≤ 0.05. z For 7.00g fruit.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
DPPH Assay
In the DPPH assay, the samples' antioxidant activity was measured using the method described by Muthiah et al. (2012) with a minor adjustment. In a nutshell, 2 ml of DPPH (2, 2-diphenyl-1-picryl-hydroxyl) was mixed with 0.2 ml of the extract. It was kept dark for 30 minutes at room temperature. The absorbance was estimated at 517 nm utilizing a spectrophotometer after 30 min. DPPH was expressed as percentage.
Data Analysis
One-way analysis of variance (one-way ANOVA) was used to determine the differences among genotypes. Duncan's multiple range test was used to compare the mean values (P≤0.01). SPSS 18 was used to analyze the statistical data. The relationships among variables were evaluated using Pearson's correlation coefficient.
Results
In this study, 2 sugars (fructose and glucose) were identified in mulberry juice by HPLC method (Fig. I, Table 1). Fructose was found in lower amounts than glucose. Mulberry's glucose content ranged from 2.97 g/100 g in genotype 3 to 5.06 g/100 g in genotype 2. Genotype 2 had a fructose content of 4.28 g/100 g while genotype 3 had a fructose content of 2.83 g/100 g. Additionally, the total sugar content ranged from 5.80 to 9.34 g/100 g.
|
Total titratable acid (TA)
Total titratable acidity ranged from 0.10 to 0.21%. The level of sugars differed significantly among mulberries (P≤0.01). The TA level in genotype 3 was significantly higher than that of the other genotypes. Ascorbic acid demonstrated the same trend. The juice's TA content was found to be lower in genotype 2. Additionally, the ascorbic acid of fruit was seen to diminish in genotype 2 (Table 1).
pH, TSS, TSS/TA and juice contents
The value of pH, TSS, TSS/TA, and juice of all samples are presented in Table 1. pH, TSS, TSS/TA, and juice showed significant differences at P≤0.01. Genotype 3 showed the most minimal mean for pH, TSS, TSS/TA while genotype 2 showed the highest mean values. In addition, genotype 3 had a higher juice percentage (60 %) than genotype 2 (47 %) in this study.
Physical traits of fruits
Table 2 Intercorrelations between 7 traits in a correlation matrix
|
Total flavonoid, total phenol and DPPH
Total flavonoids differed from 0.54 mg/g DW (genotype 2) to 0.93 mg/g DW (genotype 3). The total phenol content ranged from 1.40% in genotype 2 to 1.92 % in genotype 3. Additionally, the DPPH ranged from 17 to 22%. The values of total flavonoid, total phenol, and DPPH at P≤.01 were significantly different from one another. DPPH had the lowest values for genotype 2 while genotype 3 had the highest values (Table 1).
Results of correlations
Fructose and pH were found to be positively correlated together (r = 0.96). Moreover, TSS and fructose were found to have a strong positive correlation (r = 0.95) with each other. A positive correlation was also observed between TSS and pH (r = 0.95). TSS also showed a high negative correlation with total acid and ascorbic acid about 0.96 (Table 2).
Discussion
Findings of the study showed that content of fructose was from 2.83 to 4.28 g/100 g and the content of glucose was 2.97 to 5.06 g/100 g. Fructose and glucose contents assayed in our examination were lower than those reported by Eyduran et al. (2015), Gundogdu et al. (2018), Gecer et al. (2016), Gundogdu et al. (2011), Akin et al. (2016), and Amin and Attia (2003).
In this study, the fructose and glucose contents of the fruits in white mulberry at the full ripening stage were close to those reported by Negro et al. (2019), Aljane et al. (2016), and Mahmood et al., (2012). Negro et al. (2019) observed 3.20 g/100 g fructose and 3.20 g/100 g glucose. Aljane et al. (2016) reported 2.30 g/100 g fructose and 2.23 g/100 g glucose, and the fructose and glucose contents reported by Mahmood et al. (2012) were 4.97 g/100 and 3.21 g/100 g, respectively. Furthermore, higher glucose content was found in this study as compared with fructose in all mulberry genotypes while no sucrose was identified. The major sugar determined in white mulberry by Amin and Attia (2003), Aljane et al. (2016), and Mahmood et al., (2012) was fructose.
The titratable ascorbic acid contents of white mulberry in this study ranged from 4.00 to 7.10 mg/100 g accounting for from 0.10% to 0.21%, respectively. These values are close to those reported by Hassanpour and Firooz Barandoozi (2020) with 0.16%-0.28%, Elhami and Estiri (2009) with 0.24%-0.72%, Cocen et al. (2018) with 0.06%-0.37%, Yilmaz et al. (2012) with 0.06%-0.90%, Skender et al. (2019) with 0.01%-0.19%, Hepsağ et al. (2016) with 0.14%, Ercisli and Orhan (2007) with 0.25%, Imran et al. (2010) with 2%, Amin and Attia (2003) with 0.14%, Gungor and Sengul (2008) with 0.25%-0.28%, and Balik et al. (2019), with 1.12%-2.20% concentrations of titratable ascorbic acid in the white mulberry fruits harvested elsewhere.
There are also a number of studies that reported lower levels of ascorbic acid contents than the present study. These include 16.42 mg/100 g (Gecer et al., 2016), 13.40 to 18.22 mg/100 g (Eyduran et al., 2015), 24.42 mg/100g (Gundogdu et al., 2011), 16.68 mg/100 g (Akin et al., 2016), and 2 to 16 mg/100 g (Makhoul et al., 2017).
In this study pH contents of white mulberry ranged from 5.30 to 6.00. This is close to the findings of many studies reported around the world (Hassanpour and Firooz Barandoozi, 2020; Balik et al., 2019; Aljane et al., 2016; Hepsag et al., 2016; Gozlekci et al., 2014; Yilmaz et al., 2012; Abd EL-Malak et al., 2010; Elhami and Estiri, 2009; Ercisli and Orhan, 2009; Gungor and Sengul, 2008; Amin and Attia, 2003). On the other hand, Imran et al (2010) in their study reported a much lower pH (3.35) of the white mulberry fruit.
TSS content of the fruits under investigation in our study (9.00%-17.00%) was generally lower than those reported in the literature including 14.53%-23.50% (Balik et al., 2019), 13.53%-22.15% (Skender et al., 2019); 7.27% (Aljane et al., 2016), 21.13% (Hepsag et al., 2016), 22.59% (Bajpai et al., 2014), 17.80%-30.67% (Yilmaz et al., 2012), 17.27% (Gozlekci et al., 2014), 19.12% (Abd EL-Malak et al., 2010), 20.40% (Ercisli and Orhan, 2009), 18.50%-27.00% (Elhami and Estiri, 2009), 21.25%-28.50% (Gungor and Sengul, 2008), 16.25% (Amin and Attia, 2003). On the other hand, Ionica et al. (2017) reported a lower TSS content (12.70%) in the mulberry fruit, which is close to our finding.
White mulberry had a moisture content of 75.30%-80 % and a juice content of 47%-60 % in this study. The juice percentages in this study are similar to the findings of Yilmaz et al. (2012), which ranged from 40.67% to 64.67%. On the other hand, the juice and moisture contents were 77.72% and 79.92%, respectively in Amin and Attia (2003) showing slightly higher values for these attributes. Gungor and Sengul (2008) reported the moisture content ranging between 72.85% and 79.75%. Also, Negro et al. (2019), Skender et al. (2019), Abd EL-Malak et al. (2010), Imran et al., (2010), Elhami and Estiri (2009), and Ercisli and Orhan (2007) found that the moisture contents of white mulberry were 77.6%, 77.84%-86.46%, 76.53%, 81.72%, 69.50%-72.00%, and 71.5%, respectively. The moisture levels in the current study were higher than those reported by Elhami and Estiri (2009) and also Ercisli and Orhan (2007).
Total dry matter and ash of the fruits recorded in the current study were 20%-24.70% and 4.17%-6.00%, respectively. These results are different from those of Elhami and Estiri (2009), who found that total dry matter and ash in white mulberry were 28.00-30.50% and 1.15%-1.24%, respectively. Total dry matters of white mulberry in Ercisli and Orhan (2007), Ionica et al. (2017) were 29.50%. and 17.69%, respectively. Imran, et al. (2010) found total dry matter and ash contents of 18.28% and 0.57%, respectively in the white mulberry fruits under study. The ash content of white mulberry fruits in our study was higher than a number of studies reported in the literature including Skender et al. (2019), Gungor and Sengul (2008), Abd EL-Malak et al. (2010), and Attia (2003) who found ash contents of 0.70%-0.96%, 2.20%-2.65%, 1.27%, and 1.02%, respectively.
Fresh fruit weight was estimated from 1.18 to 2.80 g in this study. These results were near to those reported by Skender et al. (2019) who reported fresh fruit weights ranging from 1.25 g to 2.24 g. Fruit weight in the studies by Yilmaz et al. (2012), Hassanpour and Firooz Barandoozi (2020), Cocen et al. (2018), Balik et al., (2019), Ercisli and Orhan (2007), Aljane, et al., (2016), Gozlekci et al. (2014), Bajpai et al. (2014), Hepsag et al. (2016), and Amin and Attia (2003) were reported 0.66-3.07 g, 0.71-4.24 g, 0.77-2.46 g, 1.38-3.38 g., 3.49 g, 1.58 g, 2.85 g, 1.34 g, 3.85 g, and 2.59 g, respectively. The value of fresh fruit weight in our study was lower than that of Ercisli and Orhan (2007) and Hepsag et al. (2016).
Fruit length and diameter ranged from 18.50 to 25.90 mm and from 11.40 to 14.50 mm, respectively in this study. These results were within the ranges reported by Balik et al., (2019) who found white mulberry fruit length and diameter of 17.39-27.01 mm and 10.89-15.42 mm, respectively. The white mulberry fruit length and diameter ranged 16.69-26.34 mm and 8.86-14.13 mm in the study reported by Cocen et al. (2018). Hassanpour and Firooz Barandoozi (2020) found a diameter of 10.39-15.55 mm and a length of 14.48-29.60 mm. Skender et al. (2019) recorded a diameter of 5.50-7.10 mm and a length of 12.50-15.20 mm. Gozlekci et al. (2014) reported that the white mulberry fruit had a length of 22.06 mm and a diameter of 12.55 mm. The fruit length and diameter were 25.62 mm and 16.82 mm in Hepsag et al. (2016). Aljane et al. (2016) reported that the white mulberry fruit had a diameter of 13.78 mm and a length of 21.38 mm. According to Amin and Attia (2003), the white mulberry fruit had a diameter of 13.50 mm and a length of 21.30 mm. The level of total dry matter in our study was in line previously reported. Our study's fruit length and diameter were higher than those found by Skender et al. (2019).
The fruit stalk diameter and length ranged from 0.89 to 1.11 mm and from 5.81 to 7.86 mm, respectively in this study. These results were within the range found by Cocen et al. (2018), who found the fruit stalks diameter of white mulberry from 0.51 to 1.33 mm and a length of 5.56 to 11.07 mm. The stalk lengths of white mulberry fruits in studies by Hassanpour and Firooz Barandoozi (2020), Balik et al. (2019), Skender et al. (2019), Aljane et al., (2016), Gozlekci et al. (2014), and Hepsağ et al (2016) were 4.65-12.71 mm, 7.50-11.90 mm, 2.00-3.70 mm, 6.75 mm, 8.01 mm, 3.76 mm, respectively. In our study, we found a higher level of fruit stalk length than those reported by Skender et al. (2019).
Total phenol ranged from 1.40 to 1.92 mg GAE/g dry weight (DW) in our study while total flavonoid ranged from 0.54 to 0.93 mg RE/g DW. Radojkovic et al. (2012) found that white mulberry contained 4.13 mg GAE /g DW of total phenol and 0.89 mg RE /g DW of total flavonoid. Total phenol and flavonoid contents of white mulberry fruits in Bajpai et al. (2014) were 3.47 mg GAE/g DW and 0.58 mg QE/g DW, respectively.
In their study on white mulberry fruits, Aljane et al. (2016) found 13.51 mg GAE/100 g FW (fresh weight) total phenol and 8.99 mg Catechin/g FW of total flavonoids. Abd EL-Malak et al., (2010) reported that white mulberry contained 143.73 mg GAE/100 g FW of total phenol and 23.22 mg of total flavonoid per 100 g FW. According to Ercisli and Orhan (2007), white mulberry contained 181 mg GAE/100 g FW of total phenol and 29 mg QE/100 g FW of total flavonoid. Furthermore, Gozlekci et al. (2014) reported that white mulberry contained 49 GAE/100 g FW of total phenol and 37.50 mg Catechin/g DW of total flavonoids. Ionica et al. (2017) found that white mulberry contained 458.42 mg GAE/100 g FW of phenol and 78.04 mg QE/100 g FW of flavonoids. Total phenol contents of white mulberry in the study by Negro et al. (2019), Skender et al. (2019), Imran et al. (2010) were 141.2 mg GAE/100 g FW, 6.26-50 GAE/100g FW, 1650 mg/100 g FW, respectively. Total flavonoid content of our study was close to the levels reported by Radojkovic et al. (2012).
The DPPH content of white mulberry ranged from 22% to 33% in our research. Negro et al. (2019) reported similar outcomes and discovered approximately 18.50% DPPH in white mulberry. Aljane et al., (2016) found that white mulberry had DPPH levels of 66.62%, which was highly above the findings of the present study. On the other hand, Bajpai et al., (2014) found that white mulberry had DPPH levels of 4.35 mg/ml, which is remarkably lower than those in our study. Numerous variables including genotypes, environmental conditions, and other factors, influence the fruits' physicochemical traits (Gundogdu et al., 2017).
Conclusion
While application of fertilizer and irrigation affects the content of sugars in crops (Kumar et al., 2004), these operations were carried out uniform in this study so we did not believe that the variability observed in the study was a result of these factors. In the present study we found that the sugars and total acids contents were significantly affected by genotypes and there was a great variation in most of the measured characters among three mulberries. Among the three mulberries examined, genotype 2 showed the highest content of fructose and glucose. The lowest levels of fructose and glucose were produced by genotype 3.
Findings revealed useful information about genotypes' chemical composition of white mulberry, which can be utilized in the food industry and provide valuable genetic resources for breeding programs. Additionally, the evaluation of new food and a dietary supplement may benefit from the obtained results. Future diet studies examining the role of mulberries in lowering disease risk will benefit greatly from these findings. Finlay, this study may be useful to producers, breeders, and processors because it expands our understanding of phytochemical properties of mulberry fruit such as antioxidant activity and phenolic compounds among different genotypes. Further research is required for the association between genotype and sugars
Acknowledgments
The authors are grateful to Islamic Azad University, Roudehen Branch for supporting the research.
References
Abd EL-Malak, G., F. B. EL-Kasas and S. Youssef .2010. Evaluation of some mulberry species and their suitability for processing jams. Journal of Food and Dairy Sciences, 1(11): 697-707.
Akin, M., S. P. Eyduran, S. Ercisli, V. Kapchina-Toteva and E. Eyduran. 2016. Phytochemical profiles of wild blackberries, black and white mulberries from southern Bulgaria. Biotechnology & Biotechnological Equipment, 30(5): 899-906.
Aljane, F., N. Sdiri, R. Laamari, S. Ochatt and A. Ferchichi. 2016. Morphological, phytochemical and antioxidant characteristics of white (Morus alba L.), red (Morus rubra L.) and black (Morus nigra L.) mulberry fruits grown in arid regions of Tunisia. Journal of New Sciences, 35:1940-1947.
Amin, W. A. and R. Attia . 2003. Characterization of the Egyptian mulberry (Tut) fruits for preparing processed products and natural colours. Journal of Food and Dairy Sciences, 28(3): 1895-1909.
Bajpai, P. K., A. R. Warghat, P. Dhar, A. Kant, R. B. Srivastava and T. Stobdan .2014. Variability and relationship of fruit color and sampling location with antioxidant capacities and bioactive content in Morus alba L. fruit from trans-Himalaya, India. Lwt-food science and technology, 59(2): 981-988.
Balik, A., M. K. Gecer and R. Aslantas . 2019. Diversity of biochemical content in fruits of some indigenous mulberry genotypes." Turkish Journal of Agriculture and Forestry, 43(1): 28-35.
Chen, X., K. Yuan and H. Liu. 2010. Phenolic contents and antioxidant activities in ethanol extracts of Citrus reticulata Blanco cv. Ougan fruit. Journal of Food, Agriculture & Environment, 8(2): 150-155.
Çöçen, E., H. Pınar, A. Uzun, M. Yaman, A. Aslan and O. T. Altun .2018. Phenological, Pomological and Technological Characteristics of Seedless White Mulberry in Mulberry Genetic Resources of Turkey. Turkish Journal of Agriculture-Food Science and Technology, 6(10): 1317-1321.
Du, Q.-Z., J.-f. Zheng and Y. Xu .2008. Composition of anthocyanins in mulberry and their antioxidant activity. Journal of Food Composition and Analysis, 21(5): 390-395.
Elhami, R. A. and S. Estiri .2009. Evaluation of physicochemical properties and vinegar production process of two varieties of white berries in Sabzevar. Innovation in Food Science and Technology (Food Science and Technology), 1 (1), 25-40.
Ercisli, S. and E. Orhan .2007. "Chemical composition of white (Morus alba), red (Morus rubra) and black (Morus nigra) mulberry fruits." Food chemistry, 103(4): 1380-1384.
Ercisli, S. and E. Orhan .2008. Some physico-chemical characteristics of blackmulberry (Morus nigra L.) genotypes from Northeast Anatolia region of Turkey. Scientia Horticulturae, 116(1): 41-46.
Eyduran, S. P., S. Ercisli, M. Akin, O. Beyhan, M. K. Geçer, E. Eyduran and Y. Erturk. 2015. Organic acids, sugars, vitamin C, antioxidant capacity, and phenolic compounds in fruits of white (Morus alba L.) and black (Morus nigra L.) mulberry genotypes. Journal of Applied Botany and Food Quality, 88. 134 - 138
Farhangi, H., M. Ajilian, M. Saeidi and G. H. Khodaei .2014. Medicinal fruits in holy Quran. International Journal of Pediatrics 2(3.2): 89-102
Gao, X., Q. Hou and Z. Ma .2020. Differences of sugar components in Different Mulberry Cultivars during its ripening. IOP Conference Series: Earth and Environmental Science, IOP Publishing.
Gecer, M. K., M. Akin, M. Gundogdu, S. P. Eyduran, S. Ercisli and E. Eyduran. 2016. Organic acids, sugars, phenolic compounds, and some horticultural characteristics of black and white mulberry accessions from Eastern Anatolia. Canadian Journal of Plant Science, 96(1): 27-33.
Gozlekci, S., H. Uzun and A. Yegin .2014. Some physico-chemical characteristics of mulberry (Morus alba, Morus laevigata, Morus nigra) species grown in western Turkey. XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes. VI International Symposium on Human Health Effects of Fruits and Vegetables. pp: 191-197.
Gundogdu, M., I. Canan, M. K. Gecer, T. Kan and S. Ercisli .2017. Phenolic compounds, bioactive content and antioxidant capacity of the fruits of mulberry (Morus spp.) germplasm in Turkey. Folia Horticulturae, 29(2): 251-262.
Gundogdu, M., F. Muradoglu, R. G. Sensoy and H. Yilmaz .2011. Determination of fruit chemical properties of Morus nigra L., Morus alba L. and Morus rubra L. by HPLC. Scientia horticulturae, 132: 37-41.
Gundogdu, M., M. Tuncturk, S. Berk, N. Sekeroglu and S. Gezici .2018. Antioxidant capacity and bioactive contents of mulberry species from Eastern Anatolia region of Turkey. Indian Journal of Pharmaceutical Education and Research, 52(4): 96-101
Gungor, N. and M. Sengul .2008. Antioxidant activity, total phenolic content and selected physicochemical properties of white mulberry (Morus alba L.) fruits. International Journal of Food Properties, 11(1): 44-52.
Hassanpour, H. and S. Firooz Barandoozi .2020. Investigation of Physicochemical Characteristics and Fruit Color of Some White Mulberry (Morus alba) Genotypes in West Azerbaijan Province of Iran. Isfahan University of Technology-Journal of Crop Production and Processing, 9(4): 145-158.
Hepsağ, F., Ö. Gölge and İ. Hayoğlu. 2016. Effect of genotypes on chemical and physical properties of mulberry. Hacettepe Journal of Biology and Chemistry, 44(3): 225-231.
Huang, H.-P., T.-T. Ou and C.-J. Wang. 2013. Mulberry (Sang Shèn Zǐ) and its bioactive compounds, the chemoprevention effects and molecular mechanisms in vitro and in vivo. Journal of traditional and complementary medicine, 3(1): 7-15.
Imran, M., H. Khan, M. Shah, R. Khan and F. Khan. 2010. Chemical composition and antioxidant activity of certain Morus species. Journal of Zhejiang University Science B, 11: 973-980.
Ionica, M.-E., V. Nour and I. Trandafir. 2017. Bioactive compounds and antioxidant capacity of some Morus species. South-western Journal of Horticulture, Biology and Environment, 8: 79-88.
Janick, J. 2003. Horticultural Reviews, Volume 29: Wild apple and fruit trees of central Asia, John Wiley & Sons.
Kumar D., B.P. Singh and P. Kumar. 2004. An overview of the factors affecting sugar content of potatoes. Annals of Applied Biology, 145:247-256.
Lee, J.-H., J.-B. Whang, N.-R. Youn, S.-Y. Lee, H.-J. Lee, Y.-J. Kim and K.-H. Koh. 2009. Antioxidant and oxygen radical scavenging capacities of the extracts of pear cactus, mulberry and Korean black raspberry fruits. Preventive Nutrition and Food Science, 14(3): 188-194.
Mahmood, T., F. Anwar, M. Abbas, M. C. Boyce and N. Saari 2012. Compositional variation in sugars and organic acids at different maturity stages in selected small fruits from Pakistan. International journal of molecular sciences, 13(2): 1380-1392.
Makhoul, G., H. Mahfoud and H. Baroudi 2017. Some chemical characteristics of white (Morus alba L) and black (Morus nigra L) mulberry phenotypes in Tartus Syria. SSRG International Journal of Agriculture & Environmental Science, 4(2): 53-62.
Muthiah, P., M. Umamaheswari and K. Asokkumar . 2012. In vitro antioxidant activities of leaves, fruits and peel extracts of Citrus. International Journal of Phytopharmacy, 2(1): 13-20.
Negro, C., A. Aprile, L. De Bellis and A. Miceli. 2019. Nutraceutical properties of mulberries grown in southern Italy (Apulia). Antioxidants, 8(7): 223.
Paunović, S. M., P. Mašković and M. Milinković. 2020. Determination of primary metabolites, vitamins and minerals in black mulberry (Morus nigra) berries depending on altitude. Erwerbs-Obstbau, 62(3): 355-360.
Radojković, M. M., Z. P. Zeković, S. S. Vidović, D. D. Kočar and P. Z. Mašković. 2012. Free radical scavenging activity and total phenolic and flavonoid contents of mulberry (Morus spp. L., Moraceae) extracts. Hemijska industrija, 66(4): 547-552.
Şengul, A. Y., T. Şengul, Ş. Çelik, G. Şengül, A. Daş, H. Inci and A. Ş. Bengu.2021. The effect of dried white mulberry (Morus alba) pulp supplementation in diets of laying quail. Revista MVZ Córdoba, 26(1): 4-14.
Shahidi F. 2012. Dried Fruits: Phytochemicals and Health Effects, John Wiley & Sons, New York.
Singh, S. and M. Choudhary 2012. Production Technology of Fruit Crops in Wasteland, Scientific Publishers.
Skender, A., M. Kurtović, S. Ercisli and D. Bećirspahić. 2019. Some physicochemical characteristics of black and white mulberry genotypes from Bosnia and Herzegovina. Genetika, 51(3): 1089-1101.
Vaughan, J. and C. Geissler. 2009. The new Oxford book of food plants, OUP Oxford.
Vega, E. N., A. K. Molina, C. Pereira, M. I. Dias, S. A. Heleno, P. Rodrigues, I. P. Fernandes, M. F. Barreiro, D. Stojković and M. Soković. 2021. Anthocyanin’s from Rubus fruticosus L. and Morus nigra L. applied as food colorants: A natural alternative. Plants, 10(6): 1181.
Yilmaz, K., Y. Zengin, S. Ercisli, M. Demirtas, T. Kan and A. Nazli. 2012. Morphological diversity on fruit characteristics among some selected mulberry genotypes from Turkey., 22(1): 211-214.