Effect of Storage Time and Packing Method on the Freshness of Dried Lycium Fruit Using Electronic Nose and Chemometrics

Xiaojing Tian,Zhenbo Wei,Zhongren Ma,Jun Wang,Xiaoqin Bai,Shien Chen,Peng Zhang,Yuanlin Liu,Li Song,Li Luo,Ming Long

doi:10.1155/2020/6145189

Xiaojing Tian, Zhenbo Wei + Show 9 more

Open Access

https://doi.org/10.1155/2020/6145189

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Abstract

The effect of storage time and packing method on dried Lycium fruits was studied through an electronic olfactory system with the metal oxide sensor array that provides an overall perception of the volatile compounds presented in the sample headspace. Principle component analysis (PCA), canonical discriminant analysis (CDA), and cluster analysis (CA) were used for freshness and packing methods discrimination of dried Lycium fruits. The stale samples of 2015 and 2016 could be separated with those of 2017 by PCA, CDA, and CA analysis. Better discrimination results were obtained by CDA, with samples of 2015 and 2016 separated with each other. For samples of 2017, the unpackaged samples of 2017-4 were distinguished with the vacuumed samples, while samples of grade C were separated with B and D. For quantitative analysis, predictive models for prediction of the storage years of dried Lycium fruits were built with methods of partial least square (PLS) analysis, multiple linear regression (MLR), and back propagation neural network (BPNN). The model built by BPNN showed the best predict ability with R2 = 0.9994, while PLS and MLR were also effective in the prediction of storage years of dried Lycium fruits, with high determination coefficients of 0.9316 and 0.9330. These findings showed that E-nose can be used in the discrimination of the storage time and package method of dried Lycium fruits.

Highlights

Lycium barbarum L., a Solanaceae defoliated shrubbery that grows in China, Tibet, and other parts of Asia, reportedly have many health-enhancing effects, such as immune modulation, antioxidant effects, and eye health benefits [1, 2]. e dried fruits have been used as traditional medicine in China and in many countries for more than 2500 years [3]
The content of the bioactive substances in dried Lycium fruits declines with storage, such as the content of Lycium barbarum polysaccharides [4], chlorogenic acid, [5, 6], and total flavonoids [7], indicating that stale Lycium fruits weaken in terms of pharmacodynamic effects
For the quality detection of dried Lycium fruits, sensory evaluation [8], physical and chemical component analysis and fingerprint technology, and spectroscopy technology are used. It is the traditional method used for quality differentiation. It relies on the specialists and unable to give the content of internal components, which limits the application

Summary

Introduction

Lycium barbarum L., a Solanaceae defoliated shrubbery that grows in China, Tibet, and other parts of Asia, reportedly have many health-enhancing effects, such as immune modulation, antioxidant effects, and eye health benefits [1, 2]. e dried fruits have been used as traditional medicine in China and in many countries for more than 2500 years [3]. For the quality detection of dried Lycium fruits, sensory evaluation [8], physical and chemical component analysis and fingerprint technology, and spectroscopy technology are used. E complex sample pretreatment, long detection cycle, and effects by external conditions could not be ignored For spectroscopy technology, it is widely used for tracing the Journal of Food Quality origin of L. barbarum [15, 16] varieties, and species differentiation of eight Lycium species with two-dimensional infrared spectroscopic fingerprinting have been studied [17]. Gas sensor arrays are sensitive to the volatiles of samples and give a comprehensive odor fingerprint, which could be used for qualitative and quantitative analysis of the nondestructive freshness judgment of dried Lycium fruits. Dried Lycium fruits that differed in freshness were detected using the E-nose to do the following: (1) to evaluate the changes in odor of Lycium fruits due to differences in freshness; (2) to analyze the correlation between odor and freshness of Lycium fruits; and (3) to provide references and establish a new method for market surveillance of dried Lycium fruits

Materials and Methods

Results and Discussion

Findings

Conclusions