University Publications

Fruits and vegetables are considered essential food materials for human nutrition, as they are very rich in minerals, vitamins, fibers, and contain low levels of calories, proteins, and fat. In particular, the genus Citrus contains many secondary metabolites known to correlate positively with reduced risks of chronic diseases such as cardiovascular disease, diabetes and cancers. Freezing storage is considered the best and most convenient processing and preservation method for fruit juices to extend or lengthen their shelf life and preserve their fresh quality. The main goal of this study was to investigate the influence of freezing storage on the quality parameters of lime juice extracted from two lime fruits obtained from two locations in Khartoum City, Sudan. Fresh mature green and full-ripe yellow lime fruits (Citrus aurantiifolia L.) cultivars at optimal maturity with uniform size, shape and without visible infections were obtained from Tuti Island and Algaili farms. The juice was extracted using stainless steel hand-held juice squeezer and filtered through a stainless steel sieve. The juice was divided into two parts. The first part was used directly for different investigations, while the second part was stored in a -20̊ C freezer for 6 months and used for further investigations. The quality parameters such as physicochemical characteristics and sensory evaluation were determined using standard procedures. The freezing storage period was found to have variable effects on lime juice quality. The viscosity, total soluble solids and Vitamin C content remain unchanged, whereas, the pH decreases and the titrable acidity increases after freezing. The brightness and yellowness values increased, while the greenness value decreased. The juice was acceptable and not significantly affected by freezing according to the panelists’ perception. The findings of this study recommend using freezing storage for storing lime juice for a long period of time without negative effects on its quality