Effects of Pre-germination Treatment on the Phytate and Phenolic Contents of Almond Nuts

Subject Areas : Microbiology

Liang Lin Lin ¹ , Freda Xin You Giam ² , Xin Min Foo ³ , Nadia Marie Hui Lian Yeo ⁴ , Charlene Jia Ling Koh ⁵ , Nur Hatika Binte Sa’Aban ⁶ , Wai Mun Loke ⁷

1 - Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore
2 - Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore
3 - Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore
4 - Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore
5 - Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore
6 - Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore
7 - 1 Food Science & Nutrition Group, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore 2 Centre for Functional Food & Human Nutrition, School of Chemical & Life Sciences, Nanyang Polytechnic, Nanyang, Singapore

Received: 2017-05-17 Accepted : 2017-05-17 Published : 2017-05-01

Keywords: total antioxidant capacity, Phytic acid, Almond kernels, Pre-germination, Total Phenolic Content,

Abstract :

This study examined if pre-germination altered the water content and water activity, contents of phytate, total phenolic, (±)-catechin, quercetin and total antioxidant capacity of almond (Prunus dulcis)kernel. Raw almond kernels were submerged for 15 hours in water, 0.02 mol dm-3 phosphate buffer solution (pH 5.0) and 0.02 mol dm-3 phosphate buffer solution (pH 7.0) at 25 and 40ºC, respectively. The content and activity of water in the kernels before and after the pre-germination treatments were measured by oven drying and dew point water analysis, respectively. The total phenolic and phytic acid contents of the kernels were quantified by using Folin-Ciocalteu and a published spectrophotometric assay, respectively. (±)-Catechin and quercetin contents in the almond kernels were determined using gas-chromatography mass spectrometry. The total antioxidant capacity of the kernels were measured by 2,2’-diphenyl-1- picrylhydrazyl assay. Treatment with water, PBS pH 5 and PBS pH 7 significantly increased the water, total phenolic, (±)-catechin contents and total antioxidant capacity of the almond kernels regardless of the treatment temperatures (25 or 40°C). The phytic acid and quercetin contents were significantly elevated after the three treatments at 40°C. The total phenolic, (±)-catechin, quercetin and phytate contents in the almond kernels contributed significantly to its antioxidant property. Our results suggested that the phytochemical compositions of the almond kernels changed during pre-germination. The temperature and pH of the medium exert differential influence on the phytochemical compositions of the pre-germinated almond kernels.

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