Quality Detection And Safety Discrimination Of Fresh Jujube By Near-infra Red Spectroscopy

Fresh jujube is one of the favorite foods for people because of its high nutritious andgood tastes. However, fresh jujube suffers the effect of external environment and its ownfactors easily during storing which can lead to its rot and then affect its edible value andeconomic value. It is necessary to evaluate the quality change, predicted shelf life of freshjujube by establishing an effective detection method for ensuring the edible safety.The study was focused on fresh jujube, near-infrared (NIR) spectroscopy was applied toidentify the different varieties of fresh jujube and cracking fruit from intact fruit, as well asestablish NIR and kinetic models of soluble solids content, moisture, amino acids, vitamin Ccontent, yeast and mold indices, it showed that NIR spectroscopy could achieve thenon-destructive detection of fresh jujube. According to the establishment of kinetic model,shelf life of fresh jujube was predicted, it achieved quality of real-time security monitoring offresh jujube. The main research results were as follows:(1) Based on near-infrared spectral data after multiplicative scatter correction processingof fresh jujubes, multilayer perceptron artificial neural network was used to build two freshjujube varieties qualitative discriminated model in storage. It obtained high discriminationaccuracy rate, the discrimination correct rate of calibration set and prediction set were100%.Thus, near-infrared spectroscopy could achieve to identify the of Dongzao and Lizao;(2) Based on near-infrared spectral data after first derivative processing of fresh jujubes,multilayer perceptron artificial neural network was used to build qualitative discriminatedmodel of cracking fruit from intact fruit. It obtained high discrimination accuracy rate, thediscrimination correct rate of calibration set and prediction set were100%. Thus,near-infrared spectroscopy could achieve to identify the integrity of fresh jujube in storage;(3) The quantity analysis models of soluble solids content, moisture, amino acids indicesof fresh jujubes storing at room temperature and cool temperature applying near-infraredspectroscopy were optimized. It showed that the determination coefficient and predictionaccuracy of models were high. Thus, it is practicable to apply near-infrared spectroscopy ondetecting quality index of fresh jujube;(4) The near-infrared spectroscopy was used to establish quantity analysis models ofvitamin C content, yeast and mold contamination of fresh jujubes at room temperature. Thekinetic models of storage time and those indices were built by using near-infrared spectraldata. It showed the models depending on zero-order reaction had better predicted power. The shelf life of fresh jujubes was predicted by kinetic models, which could achieve real-timesecurity monitoring. Thus, it is feasible to detect fresh jujube quality non-destructively andpredict shelf life accurately.In this research, near-infrared spectroscopy and chemometric methods were used todetect fresh jujube quality indices. According to near-infrared spectroscopy models andkinetic models of fresh jujube, the fresh jujube quality variation and damage degree werefound, the quality changes of fresh jujube in the storage and transportation process werepredicted as well as shelf life of fresh jujube in the storage conditions. It provided a basis toensure quality safety of fresh jujube in transportation and storage process, detect fresh jujubenon-destructively, and ensure maximum food value and economic value.