Document Type : Original Article
Authors
1
Food science and technology Department, Faculty of Agriculture, South Valley University, Qena
2
Home Economics Department, Faculty of Specific Education, Aswan University, Egypt
3
department of food science and technology, faculty of agriculture and natural resources, Aswan university
Abstract
The aim of this study was to investigate the influence of roasting by hot air (HA) and microwave (MIW) heating on the proximate chemical composition, fatty acid and amino acid constituents, total phenolic content, polyphenol profile, and antioxidant activity (IC 50%) of Siwi date seeds. There are significant variances (P< 0.05) were observed among unroasted and roasted Siwi date seed samples, roasting process slightly affected on moisture and dry matter contents of dried date seed, while crude protein, lipids, fibre and ash contents were increased. Oil content of the roasted and unroasted date seed samples ranged between 11.87 and 14.81%. GC-MS analysis of fatty acids showed that monounsaturated fatty acids; oleic acid was the most abundant fatty acids about 42.67% in unroasted date seed, followed by saturated fatty acids such as lauric acid, palmitic acid, and myristic acid, high oleic and lauric acid. Roasting process resulted in a decrease in percentage of unsaturated fatty acids and an increase in percentage of saturated fatty Glutamic acid (Glu) was the most predominant amino acid, its content in unroasted seed was 21.00 mg/g, increased to 28.34 mg/ g after MIW roasting and decreased to 17.46 mg/g after HA roasting. The major phenolics of unroasted date seed extracts were catechin, chlorogenic, syringic and gallic acid, its content was 172.98, 100.90, 89.35 and 63.21(µg/g); respectively. Significant differences were observed among phenolic compounds of date seed extracts after roasting process where some compounds were increased others decreased after roasting in MIW oven. The L* and b*values of date seed powder and oils were significantly decreased after roasting, however a* value was significantly increased. Siwi date seed has phenolic compounds are thought to have powerful radical scavengers and might be regarded an excellent source of natural antioxidants. The dark hue of the roasted seed has colorant capabilities.
Keywords
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