The Morphological Analysis And Sunscreen Effect Of Kaki Tannin

Mopan persimmon is used as the research object, which is the main persimmonvariety of the Taihang Mountains area. In order to provide a scientific basis for thedetermination of the best extraction period in the green persimmon, this research analyzethe dynamic content change of free tannin, combined tannin and soluble solids during themature period and the relationship of free tannin’s content with the hardness、chromaticityand the postharvest storage time of persimmon. The waste residue generated in Wine andvinegar processing and the persimmon peel generated in dried persimmon processing isused as raw materials to analyze the content of combined tannin and optimize theextraction conditions of it. The kaki tannin’s sunscreen effect of the ultraviolet is alsostudied. The main results were as follows:(1)The monitoring of free tannin content changes in green persimmon fruitPersimmon fruits were sampled every10days from June25,2013to October13.The dynamic content change of free tannin, soluble solids, single persimmon fresh weightand the total free tannin is analyzed during the mature period. As the persimmon fruitmatures, the content of the free tannin has been reduced from26mg/g to near zero. Thecontent of soluble solids is also reduced as the free tannin content, which have a relevancyof92.5%. The content of total free tannin in single persimmon fruit increases at first,becomes maximum on August24, stays at the level of1970mg to2050mg in thefollowing20days, then reduces to near zero.(2) Research on the relationship of free tannin content to the hardness, chromaticityEight kinds of hardness and color persimmon fruit are selected as research object. Andthe relationship of free tannin content to the hardness, color, soluble solids content isanalyzed. The results show that the free tannin content reduces as the hardness and contentof soluble solids, which have a relevancy of98.50%and91.36%respectively. The freetannin content reduces as chromaticity increases, which has a negative relevancy of90.90%. The hardness, chromaticity and soluble solids can be used as index to evaluate thecontent change of free tannin, which will simplify the determination process.(3) Researches on the content change of free tannin during storage periodThe relationship of free tannin content, soluble solids content to storage time after isstudied during storage time at room temperature. The free tannin content of persimmonfruit decreases with the extension of storage time. In the first four days, the content of free tannins reduces at a small rate, dropping from12.51mg/g to10.58mg/g, reducing0.48mg/g every day. At the fifth day, the content of free tannins reduces at a large rate, whichdecreases2.47mg/g in one day. At the sixth day, the content of free tannins reduces sharply,which decreases5.31mg/g in a single day. The content change of soluble solids isconsistent with the free tannin, reducing from19.20mg/g to12mg/g, which have arelevancy of97.33%. The results show that the kaki tannin shoule be extracted as fast aspossible after picked for the purpose of tannin extraction. The storage time shoulds not bemore than four days.(4) Research on combined tannin extraction from the waste residue generated in Wineand vinegar processingThe waste residue generated in Wine and vinegar processing and the persimmon peelgenerated in dried persimmon processing is used as raw materials. The role of the factors(the pH value, heating temperature, heating time and water content) on tannin extractionratio is analyzed. The best extracting conditions is that heating at120℃for30minutes.For persimmon slag,0.1M HCl is the best. For persimmon peel,0.05M NaOH is the best.For extraction tannin from persimmon slag, the water content is10times’s of the slag andthe water’s pH value is pH=2.(5) Research on the protective effect of persimmon tanin to ultravioletThe prepared tannin is used as material. The tannin’s sunscreen effect on ultraviolet isevaluated by measuring the absorption value and the protection of tannin from UV damageon leaves. Results shows that the kaki tannin’s absorbance value increases as tanninsolution’s concentration increases. The absorbance decreases with the change of thewavelength from280nm to400nm. Tannin solution have a better sunscreen effect onUVB ultraviolet than UVA ultraviolet.Compared with the distilled water without tannins, tannin solution shows obviousprotection from ultraviolet damage on leaves(leek, hemerocalli and purslane). Theprotection from ultraviolet damage is remarkable with the tannin concentration of0.5%to1%. The results provide scientific evidence for the applying of kaki tannin to sunscreencosmetics.