Study On Shelf Life Of Vitamin A Capsule With Peanut Oil As The Carrier

This article is aimed at improving the stability of vitamin A capsule and extending shelf life of the vitamin A capsule. Results as follows:Firstly, capsule samples of different storage time were investigated, the results showed capsule content appear to be in this situation: the increasing of peroxide value(POV) and acid value(AV) of peanut oil and the degradation of vitamin A. The POV of capsule content far exceeded limit of national standard for peanut oil(15 meq/kg,GB 1534-2003), before vitamin A content declined to the limit of Chinese Pharmacopoeia. Since peanut oil is the main ingredient of capsule content(w%>98%), POV of peanut oil is control point of extension of vitamin A capsule’s shelf life rather than vitamin A’s degradation itself. And vitamin A capsule samples from different manufacturing process were studied at the same time. During the production cycle(typically within one week), there was no significant increase(P<0.05) of POV actually. So far, the later storage life of capsule induces the increase of POV. Futher, electron paramagnetic resonance spectroscopy(EPR) was used to monitor accelerating oxidation process of peanut oil. Results indicated the increase of POV is closely correlated to the presence of free radicals. And Induction Period(IP) does exist an obvious linear relationship with POV and EPR, correlation coefficient are 0.9885(IP-POV) and 0.9843(IP-EPR) by Rancimat. Thus, in order to extend shelf life of capsule, the effective approaches to improve stability of peanut oil and capsule content by reducing the appearance of free radicals and inhibiting of oxidation were studied. Meanwhile, ways of storage and package were optimized as well.As for raw peanut oil, the carrier, which initial oxidation degree has particular influence on degradation rate of vitamin A. Results showed that the oxidation rate of mildly oxidized peanut oil(POV﹤3 meq/kg) was significant slowly than moderately oxidized(3 meq/kg﹤POV﹤8 meq/kg) and highly oxidized(8 meq/kg﹤POV﹤15 meq/kg). IP of peanut oil is the longest by cold pressed method, compared with hot pressed method and leaching method. Phospholipid and oxidation stability of peanut oil show no evident regularity. Therefore, fresh cold pressed peanut oil was chosen as the carrier of capsule. Adding 0.02% TBHQ and 0.01% citric acid into capsule appeared to be an effective way to inhibit the production of free radicals, the IP could increase 27% and 15% respectively(under 120℃ conditions). Nitrogen package and dark storage are also economical methods to retard oxidation of capsule content, under this situation, POV of peanut oil decrease by 23% and 14%. With all these optimized means, degradation rate of vitamin A reduced by 18%.Finally, applying the above conditions into pilot production of vitamin A capsules and running Accelerated Shelf-Life Test, ASLT(30,37,45℃). Found in an oxidation process in line with the first order kinetics when taking POV as the monitoring index, and its Arrhenius equation is lnk=ln15.754-6408.8/T. Prediction model for shelf life of vitamin A was derived as Qs=(ln[POVc]-ln[POV0])/exp(15.754-6408.8/T). The results show the shelf life of 20℃ is 561 d, longer than control groups’ by 36.7%. According to this equation, POV’s theoretical value is 8.38 meq/kg in 20℃, 300 d, and the actual value is 8.05 meq/kg. So the Arrhenius equation we built has a trustworthy predictive ability. Compared with control group, POV of pilot production decreased by 30% in 300d’s storage while the content of vitamin A has no significant change(P<0.05), still at the initial level.This article provides a foundation to support for effectively extending the shelf life of vitamin A capsules.