QUALITY EVALUATION OF ZOBO (HIBISCUS SABDARIFFA) JUICE PRESERVED WITH MORINGA (MORINGA OLEIFERA) OR GINGER (ZINGIBER OFFICINALE) EXTRACTS AT DIFFERENT STORAGE CONDITIONS

Abstract

This study aimed to improve the storability of zobo juice naturally. Zobo juice infused with extracts of Moringa seeds or ginger at (0.5 and 1%), control (0% preservative) and, food vendor prepared (FVPZ) zobo were evaluated for 8 weeks. Samples were stored at ambient or refrigeration temperatures and physico-chemical, microbial load and sensory qualities of the juice were analyzed using standard methods. There were drops in pH values after pasteurization from (2.44- 2.75) to (2.31 - 2.58). Vitamin C increased with storage in preserved juice but reduced in control and FVPZ. There were significant (p<0.05) differences between samples in total titratable acidity. All of the samples had varying levels of microbial load. Microbial load of raw material ranged from (7.8×104 to TNTC), (3.0×103 to 3.0×104) and (5.6×104 to 8.0×104) CFU/g, while zobo juice on day 0 had counts ranging from (2.23×103 to TNTC); (3.0×102 to 8.0×104); (4.0×104 to 5.6×104), CFU/mL for total viable, staphylococcal and fungal count respectively. There was zero enterobacteriaceae count on day 0 but increased during storage. Moringa and ginger zobo juice overall had reduced microbial load during storage compared to zobo without preservative. On day 0 show that FVPZ was more liked: appearance (4.5), aroma (4.5), taste (4.4) and general acceptability (4.7) but scores degenerated during storage. At 8 weeks of storage, 0.5%GZ scored higher in all attributes. Refrigeration retarded microbial growth but did not influence sensory scores. Study concludes that incorporation of moringa or ginger extracts into zobo was effective in improving storability of juice but ginger preserved juice was preferred.