Further Development Of Seed Watermelon And Nutritional And Functional Property Of Seed Watermelon Peel

With the development of the society and economy, although people need thefood in sufficient numbers, they put more focus towards the nutrition, quality, safety.Seed watermelon contains lots of nourishment constituents, and because of lacking ofdeep processing, the farmers got low economic benefits. In this study, the basis ofseed watermelon nutrients were analyzed, and on this basis it processed into seedwatermelon jelly and sauce. At the same time, flavonoids and polyphenols in seedwatermelon peel were extracted, their antioxidant and resistance to ultravioletradiation were evaluated. The main flavonoids and polyphenols in the extracts werealso identified by HLPC. Our aims were to provide more detailed information andmethods to deep processing of seed watermelon.Analyzed the basis nutrients, the seed watermelon was a fruit with low sugarcontent and rich mineral element content. Results showed that the stew taste causedby heating seed watermelon juice can be removed by using vacuum concentration boilpulp. The results also showed the optimal formulation for seed watermelon jelly wereas follows: seed watermelon juice20%, saccharose5.5%, proteoglycan0.11%, jellypowder0.11%, citric acid0.14%, the jelly tastes delicious and contains the odour ofseed watermelon, has uniform color and without bubble. To obtained yellow jamsauce, saccharose was added to hydrolyze to glucose and fructose and occurredMaillard Reactions with free amino acid in seed watermelon peel and juice. When theformulation were as follows: saccharose20%, citric acid0.15%, boiling time12min.The jam tastes delicious and delicate, the paste transparent and with no clear juicespilled. The seed watermelon jelly and the jam were accorded with the relevantregulations of the state, were health and nutrition leisure food.The flavonoids from the peel of seed watermelon were extracted by differentextracting methods and extracting agents, based on the single factor experimentsorthogonal experiments were to optimize the extraction conditions. Their antioxidantactivity was assessed by reducing capacity and hydroxyl radical scavenging activity.Results showed that the suitable extracted conditions were the ratio of material tosolvent1:5, temperature60℃, and extraction time12minutes. The seed watermelonflavonoids exhibited stronger hydroxyl radical scavenging activity compared to Vc, inlow content its reducing activity was stronger than that of butylated hydroxytoluene(BHT). The main composition of flavonoids were rutin, hyperoside, astragalin.Polyphenols from the peel of seed watermelon were extracted by ultrasonic assistedmethod. The extraction condition were optimized according to the orthogonalexperiment, then their antioxidant activity was assessed by DPPH and FRAP assay,and their resistance to ultraviolet(UV) radiation was observed by E. coli solid mediumculturing experiment. Results showed that the main composition of polyphenols wasgallic acid and the optimum extracted conditions were as follows: extraction time35min, the ethanol concentration70%，temperature60℃, and the ratio of material tosolvent1:12. The results also showed that the seed watermelon polyphenols exhibitedstrong scavenging DPPH ability comparable to BHT, but its reducing ferric activitypower is stronger than BHT, and it contents certain resistance to ultraviolet radiation.