Evaluation And Software Development Of Sensory Quality Grade Of Strawberry Based On Near Infrared Spectrum

The global consumption of strawberry is increasing year by year,and the commercial value is high.However,the quality of strawberries traded in the market is uneven,and the differences between individuals are large.The traditional evaluation method of strawberry sensory quality is the lack of standardization and systematization,which is time-consuming and laborious.And it is not very easy to provide useful decision reference for consumers.This paper,taking ’ZhangJi’ and ’HongYan’ strawberry as the research object,using the sensory evaluation experiment with crucial quality indicators of a*,hardness,sugar-acid ratio as characteristic variables.NIR(10000-4000 cm-1)and Fisher linear discriminant analysis were used to establish strawberry nondestructive identification methods of sensory quality and develop the supporting software.This study provides a new method for strawberry quality standardization evaluation and strawberry quality control.And it provides technical support for further research and development of on-line detection instruments and equipment for a strawberry quality grade.The research contents and results were as follows:1.Establishment of Fisher discrimination model for the sensory quality grade of strawberry based on physical and chemical values.The sensory quality of strawberry was graded by the fuzzy mathematics comprehensive evaluation system.Fisher discriminant model for the sensory quality grade of two varieties was established with the selected key quality indexes of a*,hardness,and sugar-acid ratio as the characteristic variables for the grade evaluation of ’ZhangJi’ and ’HongYan’strawberry.The Fisher discriminant model of ’ZhangJi’ was better than that of ’HongYan’.The overall accuracy of the modeling set and the verification set of ’ZhangJi’ was 96.2%and 93.3%respectively.The overall accuracy of the modeling set and the verification set of’HongYan’ was 94.3%and 91.1%respectively.2.The establishment of strawberry quality detection and sensory quality grade discrimination model based on NIRBy using NIR and chemical measurement method,the selected vital quality index a*,hardness,sugar-acid ratio were taken as the objects.And the quantitative prediction model was established by using feature band screening and different pretreatment and modeling methods.The results show that the modeling effect based on the all-band NIR is better than that of the characteristic band.And the best prediction models are all 2-nd-pls.The Rp2 of the optimal prediction model for a*,hardness,and sugar-acid ratio of ’ZhangJi’ was 0.93,0.90 and 0.93,respectively.The Rp2 of the best prediction model for a*,hardness,and sugar-acid ratio of ’HongYan’ was 0.88,0.92 and 0.92,respectively.Combining the quantitative prediction model with the Fisher discriminant model,a sensory quality discriminant model of strawberry based on near-infrared spectroscopy was established.The results of the model show that the discriminant effect of ’ZhangJi’ is better than that of’HongYan’.In the discrimination model of ’ZhangJi’,the overall accuracy of the modeling set and prediction set was 94.2%and 91.9%,respectively.The overall efficiency for the modeling set and the prediction set of ’HongYan’ were 91.3%and 90.8%,respectively.3.Development of sensory quality grade discrimination software for strawberryThis study developed a set of strawberry sensory quality grade discrimination software using Matlab language under the Matlab R2016b platform.The models established in(1)and(2)are imported into the software.This software contains four functional modules:data import,data analysis and processing,result display,and data saving.The software and the built-in model were verified with 60 non-modeling samples of each variety.The results showed that the overall accuracy of the identification model based on the physicochemical values of ’ZhangJi’ and ’HongYan’ was 95%and 93.3%.In the prediction model based on NIR,the Rp2 of three indicators of ’ZhangJi’ is 0.88-0.91.And the Rp2 of ’HongYan’ was 0.84-0.88.The overall accuracy of ’ZhangJi’ and ’HongYan’ was 93.3%and 91.7%,respectively.The verification results show that the software can realize the purpose of discriminating sensory quality grade based on the values of a*,hardness,sugar-acid ratio,or the NIR information of strawberry(10000-4000 cm-1).And it can be applied to the software system of on-line detection instrument for the strawberry quality grade in the future.