Research On The Storage Properties Of Termitomyces Albuminosus Products

Termitomyces is a precious edible and medical wild mushrooms that is seasonal, low-producing and perishable. This study aimed at improving the use value and storage property of Termitomyces. We mainly focused on evaluating Termitomyces’s nutritive value and edible safety, predicting shelf life of Termitomyces products and analyzing the change of volatile components in Termitomyces products prepared by different processing methods and stored in different conditions, which provided references to the development of wild Termitomyces products. The main researches and results as follow:(1) The basic components of wild TermitomycesThe moisture content, ash content, crude fiber content, fat content, protein content, crude polysaccharide content, total flavonoids,total phenols and the content of free amino acid and mineral elements in Termitomyces by Chinese standards methods.(2) The quality and shelf life of frozen Termitomyces productsThe weight loss ratio, soluble solids, enzyme activity, titratable acidity, MDA, texture, L value, total number of colonies of Termitomyces slice packaged in PE/ nylon composites food bags and stored in different temperatures were detected. The sensory evaluation was regarded as the end of shelf life to establish zero level kinetic prediction models accorded with weight loss ratio and titratable acidity and one level kinetic prediction model that accorded with L value. The shelf life prediction model of titratable acidity was SL=|A/A0|/{66.35 X exp[(-2.25 X 10∧4)/(8.3144 X T)]}, the activation energy Ea was 25 X 104 J/mol. The model was tested at-20℃、-30℃、-40℃, and shelf life was 118 days,190 days,308 days respectively, the fitting degree was lower than 10%, comparing with true value, the error was relative small.(3) The quality and shelf life of Termitomyces instant soupUnder the high-temperature accelerated condition, the one level kinetic prediction model that accorded with peroxide value and acid value was established by testing the microbiology, aberration, peroxide value and acid value of Termitomyces instant soup. The shelf life prediction model of acid value was SL=|A/Ao|/{ 107.80 X exp[(-2.37X 10∧4)/(8.3144XT)]}, the activation energy Ea was 2.37X 10∧4 J/mol. The fitting degree of acid value was lower than 10%. The value of Q10 determined by changes of acid value was 1.66 that conformed to the range of 1.5-10 of dehydrated food’s Q10. Then the 180 days shelf life of Termitomyces instant soup stored at 20℃ was confirmed by extrapolation method. Besides, safe antioxidants including tea polyphenol, sodium erythorbate and VE were added to Termitomyces instant soup. The result demonstrated that those antioxidants can significantly reduce peroxide value and acid value of Termitomyces instant soup, which was beneficial to the stability of products’ quality.(4) Volatile components of wild TermitomycesVolatile components extracted by dichloromethane solvent of un-pretreated, heated and microwave pretreated Termitomyces were analyzed and compared. The result reveled that there were 54 kinds of volatile components, in which the main ingredients were 2-Methyl-l-butanol, Ergosterol, Linoleic acid ethyl ester, Hexadecanoic Acid, 1-Octen-3-o1,3-Octanone, Octadecanoic acid, 9,12-Octadecadienoic acid (Z,Z)-and so on. The alcohols that contained C8 were damaged seriously during heated and microwave pretreatments.With the assistance of microwave, volatile components of Termitomyces stored at-18℃ for 0 day,3 months and 9 months were extracted by dichloromethane solvent. Then those volatile components were compared. The data showed that 75 types of volatile component were detected, and the main components were 9,12-Octadecadienoic acid (Z,Z)-, Hexadecanoic Acid, Octadecanoic acid, Ergosta-5,7,9(11),22-tetraen-3-ol,(3.beta.,22E)-, Supraene,13-Docosenamide,(Z)-, Phenol,2,2’-methylenebis[6-(1,1-dimethylethyl)-4-methyl-and so on. The percentage of peak area of 9,12-Octadecadienoic acid (Z,Z)-, Hexadecanoic Acid in total peak area increased from 5.61%to 51.49%during freezing storage, while the content of (Z)-,Supraene and Ergosta-5,7,9(11),22-tetraen-3-o1, (3.beta.,22E) were stable. The percentage of Phenol,2,2’-methylenebis[6-(1,1-dimethylethyl)-4-methyl-in total peak area declined from 7.20%to 1.11%.