Assessment of the Effect of Ginger Flour Addition on the Chemical and Storage Stability of Soymilk

Abstract

This study evaluated the effect of adding ginger flour on the storage stability of soymilk. Fresh ginger rhizome was processed to flour by oven drying (OD), sun drying (SD) and ambient drying (AD).The ginger flour were incorporated into processed soymilk at 1 g and 2 g levels, respectively to obtain ginger spiced soymilk, which was stored for 21 days. The chemical composition and microbiological load of the soymilk were determined. The pH ranged from 6.6 to 4.7. The values decreased as storage time progressed. Total titratable acidity (TTA) ranged from 0.0015 to 0.0698 % and increased with storage time. Total soluble solids (TSS) decreased from 26.60 to 3.99 oBrix as storage time increased. Total solids (TS) decreased from 7.76 to 0.31 % during storage. The total viable counts of the control sample increased from 4.0×103 to 71×103cfu/mL while those of the treated samples increased from 0 to 33×103 cfu/mL, Coliform was not detected. Yeast and mould growth did not occur from day 0 to day 7 but increased from 2.0×103 to 5.0×103 cfu/mL on day 14 and 21, respectively. The highest microbial load was obtained in the control soymilk sample. Two grams of ginger flour preserved the soymilk better than one gram. As conclusion, the incorporation of ginger flour affected the chemical composition and microbial load of soymilk during storage at refrigeration conditions.