Liu Zhenying, Xu Liang, Song Pingping, Wu Cui, Xu Bo, Li Zhuojun, Chao Zhimao
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
Foods. 2022 Aug 3;11(15):2320. doi: 10.3390/foods11152320.
To comprehensively evaluate the quality of medicinal and edible Ziziphi Spinosae Semen (ZSS, the dried ripe seeds of Ziziphus jujuba var. spinosa) before and after rancidity during storage, some indicators including traditional sensory properties, physicochemical characteristics, and volatile compounds were analyzed. As a result, compared with the normal samples, the rancid samples of ZSS produced a darker color, a bitter taste, and an irritating odor, increased moisture content, electrical conductivity, fatty oil content, and acid value, and decreased water- and alcohol-soluble extract contents and pH value. Among them, the acid value had significant difference (p < 0.01) from 3.90 of normal ZSS to 18.68 mg/g of rancid ZSS. A total of 39 volatile compounds were identified in samples, including 20 in normal ZSS and 38 compounds in rancid ZSS. Nineteen common compounds were identified in normal and rancid samples. Among them, the content of 10 compounds such as δ-limonene, (R,R)-2,3-butanediol, and (R,S)-2,3-butanediol was decreased but that of nine compounds such as acetic acid, n-octanoic acid, and n-nonanoic acid was increased in rancid ZSS. Nineteen unique compounds such as β-phellandrene, α-pinene, and 3-carene were detected and only one compound, δ-cadinene, was not detected in rancid ZSS. In addition, eight short-chain organic acids, acetic, propanoic, butanoic, pentanoic, hexanoic, heptanoic, octanoic, and nonanoic acids, were new products in rancid ZSS, and it was speculated that the production of a series of organic acids might be the material basis of irritating odor after normal ZSS became rancid. This is the first report that a series of short-chain organic acids have been found in a rancid substance. In conclusion, there was a significant difference between normal and rancid ZSS. These indicators could be used as an early warning for judging the rancidity phenomenon of medicinal and edible ZSS. In addition, this is the first comprehensive evaluation about the rancidity process of a medicinal and edible substance.
为全面评价药用和食用酸枣仁（ZSS，酸枣干燥成熟种子）在储存过程中酸败前后的质量，对其传统感官特性、理化特性和挥发性成分等指标进行了分析。结果表明，与正常样品相比，酸枣仁酸败样品颜色变深、味道变苦、产生刺激性气味，水分含量、电导率、脂肪油含量和酸值增加，水溶性和醇溶性提取物含量及pH值降低。其中，酸值差异显著（p<0.01），正常酸枣仁酸值为3.90，酸败酸枣仁酸值为18.68mg/g。样品中共鉴定出39种挥发性成分，正常酸枣仁中鉴定出20种，酸败酸枣仁中鉴定出38种。正常和酸败样品中鉴定出19种共有成分。其中，酸败酸枣仁中δ-柠檬烯、（R,R）-2,3-丁二醇和（R,S）-2,3-丁二醇等10种成分含量降低，而乙酸、正辛酸和正壬酸等9种成分含量增加。检测到β-水芹烯、α-蒎烯和3-蒈烯等19种特有成分，酸败酸枣仁中仅未检测到δ-杜松烯一种成分。此外，乙酸、丙酸、丁酸、戊酸、己酸、庚酸、辛酸和壬酸8种短链有机酸是酸败酸枣仁中的新产物，推测一系列有机酸的产生可能是正常酸枣仁酸败后产生刺激性气味的物质基础。这是首次报道在酸败物质中发现一系列短链有机酸。综上所述，正常和酸败酸枣仁之间存在显著差异。这些指标可作为判断药用和食用酸枣仁酸败现象的预警。此外，这是首次对药用和食用物质酸败过程进行的综合评价。
