The Main Changes In The Chemical Composition And Its Aging Mechanism Of Lotus Seeds During Storage

Lotus Seed has always been regarded as precious foodstuff for its rich nutritionhealth care ingredients and high medicinal value,but like other grains,agingdeterioration also occured during the storage of lotus seeds. Leading to its taste andnutritional value were far less than fresh lotus seeds.This situation seriously impactedon chinese lotus’ industry development and people health. Institute of Science inJiangxi Guangchang provided lotus seed for the material. Using GC-MS, HPLC-RI,SDS-PAGE electrophoresis and amino acid analyzer to analysis and systematic studyof the changes of lipid and soluble sugar content, relative molecular weight proteins,amino acids and protein concentrate properties in the lotus seeds during storage, anddiscussing its aging mechanism.The main results were as follows:1，Using2008,2009and2010lotus seeds as experimental material and takingthe same method as Zhang Min to follow-up study the changes of fat during storagefor3years. The results showed that crude fat content had decreased progressivelyand total free fatty acid content had increased significantly during storage. the2010lotus seeds fatty acid value increased117.56%;2009lotus seeds increased44.72%;2008lotus seeds increased78.06%. In the storage process, the unsaturated fatty acidslike linoleic acid, linolenic acid and peanut oil acid content decreased, but oleic acid,lignceric acid and stearic acid content increased. Under the action of the enzyme orlight and heat, lipids might be hydrolyzed into fatty acids.The unsaturated fatty acidsare oxidized to aldehydes, ketones, carbonyl compounds, result in odors. It was themain reason for stale rice food taste worse that the fatty acid content increased. Underthe action of enzymes, linoleic acid in membrane phospholipids was degraded,and thebalance of membrane lipids was breaked,result in promoting degradation ofmembrane lipid and accelerating aging.2，Significant changes occured lotus seeds soluble sugar content during storage.Sucrose and fructose content gradually increased.Maltose content of the first yearstorage had a sharp decline more than87.21%, and did not change significantly afterfour years; glucose content did not change significantly. An increasing of sucrosecontent might because of other sugars’ hydrolysis, hydrolysis of disaccharide result inmaltose content decreased and fructose content increased. Glucose might be due tothe lotus seed respiration while maintaining stable levels. The total content of mono-and disaccharides upward trend may be due to macromolecular carbohydratesbreak down into simple sugars and disaccharides during storage. The ratio of maltoseand sucrose was up the maximum (30.02%) in fresh lotus seeds.With the extension ofstorage time, the ratio becomes smaller.Maltose during storage could preventcrystallization of sucrose, and sucrose in a crystalline state could be slow aging rate,the lower the degree of crystallization, aging is smaller. Maltose content of fresh lotusseeds was the highest, and sucrose was the lowest. Therefore, the greater the ratio ofmaltose and sucrose, indicating that aging is smaller.Thus, soluble sugars could serveas a good indicator of the evaluation of seed aging.3，The optimal conditions for the extraction of soluble proteins lotus:PH11,ratioof lotus to solution1:30,extraction time2h,extraction temperature25℃.UsingQuantity One software to analyse lotus extract protein electrophoretic bands.Therewere the lowest similarity between the fresh and storage5years lotus seeds, and hadthe most obvious differences between them. The number of bands reduce graduallywith the extension of storage time. Molecular weight between26-43KDa of theprotein content became less. Amino acid analysis showed that the fresh lotus seedshad the highest amino acid content and nutritional value. After the storage period, thehydrophobic amino acids present first rise after a downward trend. Basic, acidic andneutral hydrophilic amino acids were showing a downward trend. During storage, alarge number of thiol changed into disulfide bonds, and the hydrophobic amino acidcontent increased result in reducing the solubility of the protein molecule.4，We found that with the extension of storage time, lotus seeds protein’s Waterabsorption capacity(WAC) and oil absorption capacity(OAC) were showing adownward trend. Emulsifying capacity(EC) and emulsion stability(ES) declined.Description that the structure and conformational of proteins from lotus changed instorage time, affecting their functional properties.This paper found that the changes of composition lead to changes in thecomponents of the cell structure of their organization during storage in lotus seeds bymeasuring lipids, soluble sugar and protein content.These changes were mutualimpact,restraint,and common cause taste and quality deterioration in lotus seeds. Morein-depth understanding the aging mechanisms of lotus seeds, and providing atheoretical basis for future lotus seeds storage and preservation.