EVALUATION OF PHYSICO-CHEMICAL PROPERTIES OF SOME MIXTURE JUICES

This study was carried out to investigate improving and developing mixed fruit juices prepared from mango, strawberry, pineapple, orange, and pomegranate  with different ratios as well as having nutritional values with highly functional and organoleplicolly characteristics. Development of new technologies for thermal food treatment is still of great industrial and scientific interest. Microwave heating is one of these new technologies. The fruits blended juices were pasteurized by two different methods, i.e. conventional processing at 80°C for 10 min and microwave heating (2450 MHz) using 100% and 70% capacity for 3min. After thermal processing, juices were stored at 4°C and analyzed after processing and storage. The physicochemical parameters studied were pH value, total soluble solids (TSS) and titratable acidity (TA) along with an estimate of metal elements such as iron, potassium, calcium, phosphorus, zinc. These juice mixtures were analyzed for their (vitamin C, antioxidant total phenolic and total flavonoid). The obtained results revealed that fresh strawberry has high content of antioxidant activity (%), total phenolic, total flavonids followed by fresh pomegranate and pineapple, respectively. Meanwhile fresh mango was higher in total soluble solids (TSS) and pH value and as well as lowest in titratable acidity (TA). Factors affecting physical, and chemical and quality of juices were studied after processing and storage as well as microbiological evaluation. Results showed no presence of viable microorganisms (total count, mold and yeast) after storage at 4°C in all treatments. Also results showed that conventional treatment led to a significant decrease in vitamin C and total anthocyanins while microwave pasteurization preserved these compounds. Also it found that microwave pasteurization at 100% capacity recorded the highest values in each of antioxidant activity, total phenolic, total flavonids and total soluble solids (TSS) compared to pasteurization on the capacity of 70%.