Spectral Characteristics Analysis Of Fruit Texture Of Tomato In Storage Period

Near infrared spectroscopy as a rapid nondestructive testing technology applys widely. Tomato quality will change in postharvest storage.This paper introduces near infrared spectrum detection with time saving and simple operation because of traditional chemical detection method with tedious and low accuracy. In this study, combining near infrared spectroscopy with principal component analysis and two-dimensional correlation spectroscopy analyses qualitatively the influence of temperature on the quality of tomato.And combining chemometrics with near infrared spectroscopy detection analyses quantitatively tomato fruit texture modeling in cold storage. Finally, we establish the kinetics model of the flesh average hardness.This paper collected near infrared spectroscopy of the tomato samples under different storage modes (normal temperature, cold, frozen) for 5 days and at harvest. Analyse the spectra change trend,the result indicated the similar trends, with obvious processes in the band of 980,1200,1450,1780,1930,2300nm.In the entire wavelength range (350-2500nm), the characteristic peak position of room temperature storage and cold for 5 days was unchanged.But the characteristic peak position of freezing storage for 5 days occurred migration, especially the peak of 980,1200,1450,1930nm. The offset phenomenon was mainly caused by structural changes of chemical substances of tomato using principal component analysis.The influence of temperature on the storage life of tomato is explained using principal component analysis and two-dimensional correlation spectroscopy.The influence is mainly caused by the three bands of 1830,960,1150nm using principal component analysis.The sensitive bands caused by temperature change is mainly 969nm,1161nm,1530,1839nm,1990nm and 2249nm using two-dimensional correlation spectroscopy analysis.Describing the weight loss rate, near infrared spectral changes in storage period and fruit texture changes in order to analyze the effect of the quality of tomato in storage period. Weightlessness in storage at normal temperature compared to the low temperature storage is the fastest. Near infrared spectral change trend in storage period is similar.Tomato fruit texture decreased with the extension of storage time during storage.Establish the quantitative analysis model of fruit texture (the flesh average hardness, pericarp breaking force, pericarp brittleness, pericarp toughness) using the leverage correction combined with partial least squares.The prediction correlation coefficient of the flesh average hardnessis 0.761, RMSEP is 0.173;the prediction correlation coefficient of pericarp breaking force is 0.809,RMSEP is 0.820; the prediction correlation coefficient of pericarp brittleness is 0.803,RMSEP is 0.831; prediction correlation coefficient of pericarp toughness is 0.764,RMSEP is 0.427, the prediction effect is good.Establish the kinetics model of the flesh average hardness at normal temperature and cold storage based on the near infrared spectroscopy. The kinetics model of the flesh average hardness at normal temperature storage is At= 1.027+0.088A0 - 0.055t, the correlation coefficient was 0.988, the root mean square error is 0.038.The storage time can be expressed as t= 18.700 - 18.208At+1.603A0.The tomatos stored at room temperature for 9 days lose edible value because of the flesh hardness down to 150kPa.Similarly,the kinetics model of the flesh average hardness at cold storage is At= 1.576+ 0.119A0 - 0.063t, the correlation coefficient was 0.966, the root mean square error is 0.114.The storage time can be expressed ast= 25.056 - 15.896At+1.899A0.The tomatos stored at room temperature for 16 days lose edible value because of the flesh hardness down to 150kPa.