| Sweet potato (Ipomoea batatas L.) leaves, stalks and stems are found to be rich in nutritiveand functional components, including protein, dietary fiber, minerals, vitamins, total polyphenolsand chlorogenic acid. Sweet potato leaves (including leaf and stalk) and stems are used as foragebut not food in many countries and areas. In China and many other Asian countries, sweet potatoleaf stalks may be found in restaurants, eateries and meals of populace as a special vegetable. Itsconsumption in China is increasing, especially in the harvest season. However, these leaf stalksare highly perishable after fresh-cut processing. To our knowledge, there is no study focusing onthe postharvest quality changes of this crop during storage. In this study, sweet potato (Ipomoeabatatas L.) leaf stalks were cut into 20 cm length, and stored at 20 ℃, 6℃ and 2℃. Respirationrate, ethylene production, ascorbic acid (AA), free amino acid, total chlorophyll contents,freshness and shelf life were determined during storage to investigate the effect of storagetemperatures on quality and physiological responses. Wound responses were observed as highrespiration rate and ethylene production immediately after cutting. Sweet potato leaf stalks werefound to be sensitive to chilling injury manifested as browning and water-soaking on the surface at2℃. In contrast, sweet potato leaf stalks were susceptible to senescence that was accompanied byetiolation and wilting symptoms at high storage temperature (20 ℃). Losses in weight andchlorophyll content were slower at low temperatures. Higher temperatures also caused theaccumulation of amino acids, and significant loss of ascorbic acid and chlorophyll contents. Sweetpotato leaf stalks had a storage life of 16 days at 6℃, 8 days at 2℃, and 6 days at 20℃,respectively.Sugarcane juice is rich in nutritive components, and it is fit to be processed into beverage. Fresh sugarcane (Saccharum officinarum) juice is popular in many countries as a cheap and sweet beverage. It is becoming a fashion juice served at roadside stalls, cafeterias and restaurants throughout China during the harvest season. However, processing and marketing of sugarcane juice is limited by its rapid deterioration. Development of effective treatments or procedures to keep the fresh quality of sugarcane juice would allow it to be more widely marketed, and would enhance its quality and safety as well. During processing and storage of fresh sugarcan juice, mostly enzymatic browning and microbial contamination led to deterioration, which we selectblanching and ascorbic acid and storing at low temperature storage to prevent. The physicochemical changes in fresh sugarcane juice stored at 10°C were studied by determining juice yield, color, reducing sugar, titratable acidity, viscosity, pH, polyphenol oxidase (PPO), sucrose neutral invertase (SNI) and total microbial count. Results showed that blanching of stems before squeezing effectively prevented browning, reduced PPO and SNI activities in fresh sugarcane juice. Added ascorbic acid delayed the increase of reducing sugar, titratable acidity, viscosity and total microbial count, and also prevented browning with reduced PPO and SNI activities in fresh sugarcane juice during storage. Addition of 0.1% ascorbic acid seemed to be more effective than blanching of sugarcane stems, and was able to maintain the quality of fresh sugarcane juice for up to 5 day at 10°C. Deterioration of fresh sugarcane juice was demonstrated as a rapid increase of titratable acidity and viscosity with a slight browning and total microbial count large than Iog5.0 cfu/g. And we have constituted technological process and quality standard of sugarcane beverage.
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