Effect Of Different Storage Ways On Yam Quality

For yam is thin and tender, it is easily spoiled after harvest and sprouted whenApril or May of spring, so that the edible quality and the large-scale storage areinfluenced, so far, the application of new storage technology and the change of yamphysiology quality and nutritional quality indexes plus to pasting properties duringstorage haven’t been reported systematically. This paper used three storage ways ofconvention, compound rhubarb-coptis extract and suckercide, under the condition of4℃,15℃and room temperature, besides the spraying conduct of0,0.5%and1%calcium chloride solution, specially designed orthogonal experiment and arrangednine experimental groups, for the storage period of180days, various quality indexesof yam were determined every other45days; moreover, the effect of suckercides withdifferent concentration and plant extracts on yam quality was also researched, so as toscreen the best concentration and natural preservative agent. The results showed:After storing for180days, yam’s sprouting didn’t happen under4℃and15℃,varying degrees of germination occurred under room temperature, but thegermination index was low, the value of suckercide group under room temperaturewas the lowest; with the prolonging of the storage time, yam respiration intensity,PPO activity, POD activity, malondialdehyde content, cell membrane relativepermeability and soluble protein content overall offered upgrade firstly thandescending latter tendency; weight loss rate was on the rise, while the content ofcrude polysaccharide, total soluble sugar, starch, oligosaccharide, protein, Vc and theaberration ΔE*of yam fresh cut surface roughly were on a decline curve; the peakviscosity, minimum viscosity and final viscosity under4℃took a downward trend aswell, while the condition of15℃and room temperature were first increased and thendecreased.The main influence factors of yam various quality indexes were storagetemperature and storage time. Compare the three temperature, low temperaturestorage could keep lower respiration intensity, weight loss rate and PPO activity, atthe same time maintain higher POD activity, crude polysaccharide content, totalsoluble sugar content, starch content, oligosaccharide content, protein content and Vccontent; low temperature storage also had a more obvious effect on keeping the pasting properties of yam; yet due to the impact of chilling damage, cold conditionwas liable to harm the membranal completeness, so that cell membrane relativepermeability and malondialdehyde content were on the high side, the aberration under4℃was higher than the value under15℃and room temperature, suckercide conductcould reduce the aberration; therefore, as far as this research material, the storagetemperature should choose above4℃,7℃or so might be ideal, and this need to beresearched.Compared to conventional storage, the conduct of compound and suckercidesplayed certain part in keeping yam better physiology quality, nutritional quality andpasting properties. But for physiology quality, the CaCl2used cooperatively wassuggested to choose lower concentration, while with nutritional quality and pastingproperties higher concentration was appropriate.For comprehensive Consideration, in the range of this experiment the suckercideconcentration screened was1.0g/kg of powder or150times of cream, and selectedcompound rhubarb-coptis extract as natural preservative agent. The best storagecondition of yam was:7℃(recommendatory temperature) along with compoundrhubarb-coptis extract and the CaCl2solution treating of0.5%.