While it is easy to rotten resulting from numerous factors including the enzyme reaction and microbial reaction during its storage,transportation and varied fine processes,pork is one of the main meat products daily consumed in China,.Conse-quently,before brought onto the dinner table,the pork bought from the market may be not fresh,which will not only affect the taste but also human health.Pork freshness is considered as one of the major driving factors for consumers to buy or not.There-fore,it is very important and also urgently needed to detect pork freshness in situ timely,quickly and accurately in order for con-sumer's food safety.Compared to traditional physical and chemical testing methods operated in laboratory,the novel visibleear-infrared spectral analysis technology for detection of cold fresh pork quality has attracted wide interest recently,due to-fea-tures quickness,high efficiency,non-destruction and non-contact of the visibleear-infrared spectral analysis technology.And hence it is more suitable for food safety quick-detection.However,most of current researches have focused on the spectral model development based on statistical methods,which results in lack of physical meaning and poor applicability,and hence hinders the application and popularization of the spectroscopy technology.The visibleear-infrared spectral features of pork with varied freshness were investigated in this paper.On this basis,a pork freshness spectral feature index(FI)was constructed using the stable absorption property of pork myoglobin at 760 nm.Additionally,the sensitivities of FI to spectral resolution and signal-to-noise(SNR)were analyzed by simulations.Our research indicated that FI was simple but had a clear physical meaning,and can become a good proxy of pork freshness.Furthermore,the FI showed a relative low dependency on the spectrometer's key prop-erties,such as spectral resolution and SNR.It may work well as long as the spectral resolutions at both 760 nm and adjacent bands are better than 10 nm,and the SNRs are no lower than 45:1.This study may provide a scientific basis for the design and development of low-cost and handheld portable spectrometers aiming for pork freshness quick detection in consumer markets.%猪肉是我国居民最主要的消费畜肉产品,其在储藏、运输、加工等环节易受酶、微生物等作用腐败变质,导致新鲜度下降.冷鲜猪肉的新鲜度关系着消费者的食肉口感与安全,是消费者购买猪肉最为关心的指标之一.及时、快速、准确检测冷鲜猪肉的新鲜程度是确保消费者"舌尖上的安全"的重要举措.相比于传统的理化检验方法,可见-近红外光谱分析技术具有快速、高效、无损、非接触等独特优势,适合于食品安全的快速检测,光谱快检技术已成为冷鲜猪肉品质无损检测的研究热点.然而目前研究大都基于统计方法进行光谱建模,模型缺乏物理意义,适用性差,阻碍了该技术的应用推广.通过分析不同新鲜程度猪肉的可见-近红外光谱特征,利用反映猪肉新鲜度的肌红蛋白在760 nm处稳定的吸收特性,构建了猪肉新鲜度光谱特征指数(FI);通过模拟不同光谱分辨率与信噪比水平,进一步探索了FI指数对光谱检测设备性能的敏感性.研究表明,FI指数构建简单,物理意义明确,能够较好指示猪肉的新鲜程度;且该指数对光谱仪的性能要求并不严苛:只要在760 nm及附近波段,光谱分辨率优于10 nm,信噪比不低于45,即可较好反映猪肉新鲜水平.研究结果可为低成本、手持式简易的猪肉新鲜度光谱检测设备的设计与研发提供科学依据,有望在食品安全快速检测领域得到推广应用.
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