The Effect of Water and Ethanol Extracts of Ginger and Garlic on the Nutritional Quality and Physico-Chemical Properties of Stored Soymilk

Abstract

Soymilk is an aqueous, white, creamy extract produced from soybeans (Glycine max). It is a highly nutritious food drink which contains protein, fat, carbohydrates vitamins and minerals. Recently, there has been an increased demand for foods having long shelf-life but with presence of minimum or no chemical food additives; therefore, the use of natural preservatives especially culinary herbs and spices in food products has increased. This study set out to investigate the effect of aqueous and ethanol extracts of ginger and garlic on the nutritional properties of soymilk before and after two weeks of storage. The soymilk was prepared using hot extraction method and each sample labeled A, B, C, D and E according to the extract they contain; ginger-ethanolic, ginger-aqueous, garlic-ethanolic and garlic-aqueous respectively while sample E served as the control containing no extract. The samples were stored at ±4°C for sixteen (16) days. The result obtained showed no significant difference (P<0.05) in the % protein, % fat and % ash contents of all the fresh samples when compared with the control. However, after the storage period, there was significant (P<0.05) decrease in the content, % fiber content, % protein content, % carbohydrate, and % fat contents of almost all the treated samples when compared with the control. A significant increase was also observed for the pH value for all treated samples after the storage period when compared with the control, although samples A and D showed a significant increase after the storage period. Samples A, C, and D, showed a significant reduction in % TTA when compared with the control after the storage period.