| Jujube(Ziziphus jujuba mill.)is the mature fruit of Ziziphus jujuba mill.This food is rich in various nutrients,such as carbohydrates,organic acids,minerals and vitamins,also included are polysaccharides,cyclic AMP,polyphenols and triterpenoids,which are highly potent and are considered to be excellent dietary supplement,and therefore of great edible and medicinal value.Dry processing is one of the most effective methods to extend the shelf life of Chinese jujube because of its high moisture content and easy water loss,shrinkage and decay.At present,there are many reports about the changes of fresh jujube storage quality,but there are few reports about the changes of dry jujube storage quality.In this study,dry jujube was used as test material to establish the analysis method of physical and chemical quality of dry jujube,which was packed in Polyethylene Bag(PE),polyethylene(PE)and polyethylene terephthalate(PET)composite bag,vacuum bag and aluminum foil bag,the variation regularity of physical and chemical quality of dried jujube during normal and low temperature storage was analyzed,and the variation regularity of physical and chemical quality of dried jujube during storage was mastered,the effects of packaging materials on the physical and chemical quality of dried jujube during storage were studied.These results can provide theoretical reference for processing and improving the physical and chemical quality of dried jujube during storage.The main conclusions of the study are summarized as follows:1.The effect of packaging materials on the physical and chemical quality of dried jujube during normal temperature storage.The effect of storage time on most of the physical and chemical quality of dried jujube had significant difference(P < 0.05),glucose,fructose,sucrose,c AMP,c GMP,GABA,total flavonoids,catechin,chlorogenic acid,P-Hydroxybenzoic Acid,p-coumaric acid,ferulic acid,rutin,quercetin and quercetin decreased gradually with storage time,the contents of total acid,HMF,total phenol,protocatechuic acid,epicatechin,ellagic acid,caffeic acid,DPPH and ABTS increased with the storage time The moisture content of vacuum bag and aluminum foil bag and VC,phloem and Kaempherol of all treatments had no significant changes during storage(P > 0.05),however,the moisture content of PE and PE + PET package decreased gradually with the storage time,and the moisture content of PE package was the fastest,the moisture content of PE package was only 7.87% at the end of storage.The effect of different packaging materials on the physical and chemical quality of dried jujube was not significant(P > 0.05),the difference of most physical and chemical indexes of dried jujube increased gradually,especially when stored at room temperature for 8 months or more,the difference of most physical and chemical indexes of dried jujube in different package treatment was significant(P < 0.05).At the end of storage(12 months at room temperature),PE package dried jujube moisture,glucose,fructose,Sucrose,c AMP,c GMP,GABA,total flavonoids,catechin,chlorogenic acid,P-Hydroxybenzoic Acid,p-coumaric acid,ferulic acid,rutin,quercetin and quercetin were significantly higher than those of the other three package dried jujube varieties(P < 0.05),PE + Pet was the second,but there was no significant difference between vacuum bag and aluminum foil bag(P > 0.05);the contents of total acid,HMF,total phenol,protocatechuic acid,epicatechin,ellagic acid,caffeic acid,DPPH and ABTS in PE-packed dried jujube were significantly lower than those in other three kinds of packed dried jujube(P < 0.05),PE + Pet was the second,but there was no significant difference between vacuum bag and aluminum foil bag(P >0.05).It is concluded that PE packaging is more beneficial to the stability of physical and chemical quality of dried jujube during storage at room temperature.2.The effect of packaging materials on the physical and chemical quality of dried jujube during low temperature storage.The levels of VC,glucose,c AMP,c GMP,GABA,total flavonoids,catechin,chlorogenic acid,P-Hydroxybenzoic Acid,p-coumaric acid,ferulic acid,rutin,quercetin and quercetin in all treatment groups decreased gradually with storage time,the contents of total acid,HMF,total phenol,protocatechuic acid,epicatechin,ellagic acid,caffeic acid,DPPH and ABTS increased with the storage time The fructose and sucrose contents in all treatment groups had no significant changes during storage(P > 0.05).The effects of different packaging materials on the physical and chemical quality of dried jujube were not significant(P > 0.05),but with the prolongation of storage time,the effect of different packaging materials on the physical and chemical quality of dried jujube was not significant(p & GT.05),the difference of most physical and chemical indexes of dried jujube in different treatments fluctuated,and the difference of most physical and chemical indexes of each treatment group was not significant when stored at low temperature for 6 months.After 6 months,the difference appeared again,and at 12 months,most of the physical and chemical indexes of dried jujube had no significant difference(P > 0.05).At the end of storage(12 months of low temperature storage),the moisture content of dry jujube packed with aluminum foil was almost the same as that at the beginning of the experiment,and the moisture content of dry jujube packed with PE was the most decreased.The contents of total acid,VC,Camp,HMF,total flavone,chlorogenic acid,P-Hydroxybenzoic Acid acid,epicatechin and ellagic acid were higher than those of the other three packaging materials,the dry red dates in vacuum packaging materials were the second,but the difference among the indexes of the four packaging materials was not significant.The contents of fructose,glucose,sucrose and GABA in PE + PET package dried jujube were higher than those in other three package materials,but the difference among the four package materials was not significant.The results showed that the packaging materials had little effect on the quality of dried jujube during low temperature storage. |
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