An automated non-destructive prediction of peroxide value and free fatty acid level in mixed nut samples

This study aimed to develop an automated technique, which is rapid, non-destructive and inexpensive, to test for rancidity of nuts. A visible to near infrared benchtop hyperspectral camera was used to capture images from blanched canarium, unblanched canarium and macadamia samples. Support vector machine classification (SVC) and PLSR models were developed to segregate the pooled spectra of the nuts and predict their peroxide values (PV) and free fatty acid (FFA) concentrations. The SVC and PLSR models were then used in a hierarchical model to develop an automated system for predicting PV and FFA. The automated model was then tested using a test set providing classification accuracy of 87% and R2 between 0.60 and 0.76 and RPD between 1.6 and 2.7 for PV and FFA prediction. Overall, the automated system has the potential commercial application in nut processing to detect rancidity of mixed nut samples non-destructively and in real-time. It is suggested to train other machine learning models with more samples to improve the accuracy of predictions

Influence of indigenous ripening methods on quality and shelf life of bananas

A laboratory study was carried out at Midlands State University, Gweru, Zimbabwe. The main objective of the study was to determine the most effective indigenous method of ripening bananas. The parameters measured were number of days taken by the bananas to reach colour plate number 6, the Total Soluble Solids (TSS) after the ripening of bananas and shelf life. The indigenous methods used were acacia leaves, tomatoes, and ashes mixed with water, banana leaves and banana fingers taken from the bunch left to ripe naturally (untreated control). The conventional ripening, of the application of ethrel was used as a positive control. There were significant differences (P = 0.001) on the number of days taken to ripen bananas, and on the shelf life of bananas ripened using the different methods. Banana fingers from the untreated bunch had the highest total soluble solids percentage (11%) followed by bananas treated with ashes mixed in water with (10.167%). There were significance differences (P = 0.001) on banana colour using different indigenous methods. Considering the ripening colour, use of tomatoes and ethrel showed the best colour. It is therefore recommended that the use of ripe tomatoes be adopted by smallholder farmers. Ethrel treated banana fingers and the untreated banana fingers showed highest days for banana shelf life. The results of the study showed that ripened tomatoes can be used in ripening of bananas in as much the same way as ethrel

Influence of indigenous ripening methods on quality and shelf life of bananas

A laboratory study was carried out at Midlands State University, Gweru, Zimbabwe. The main objective of the study was to determine the most effective indigenous method of ripening bananas. The parameters measured were number of days taken by the bananas to reach colour plate number 6, the Total Soluble Solids (TSS) after the ripening of bananas and shelf life. The indigenous methods used were acacia leaves, tomatoes, and ashes mixed with water, banana leaves and banana fingers taken from the bunch left to ripe naturally (untreated control). The conventional ripening, of the application of ethrel was used as a positive control. There were significant differences (P = 0.001) on the number of days taken to ripen bananas, and on the shelf life of bananas ripened using the different methods. Banana fingers from the untreated bunch had the highest total soluble solids percentage (11%) followed by bananas treated with ashes mixed in water with (10.167%). There were significance differences (P = 0.001) on banana colour using different indigenous methods. Considering the ripening colour, use of tomatoes and ethrel showed the best colour. It is therefore recommended that the use of ripe tomatoes be adopted by smallholder farmers. Ethrel treated banana fingers and the untreated banana fingers showed highest days for banana shelf life. The results of the study showed that ripened tomatoes can be used in ripening of bananas in as much the same way as ethrel

Hyperspectral imaging predicts free fatty acid levels, peroxide values, and linoleic acid and oleic acid concentrations in tree nut kernels

Imaging technologies are advancing rapidly in food processing systems to reduce food waste. However, modelling techniques, sample sizes and dataset proportioning methods significantly affect the performance of models in predicting food quality variables. This study examined the potential of hyperspectral imaging to predict peroxide values (PV), free fatty acid (FFA) levels and fatty acid concentrations, including oleic and linoleic acid, in two tree nuts, canarium and macadamia. The effectiveness of artificial neural network (ANN) regression and partial least squares regression (PLSR) techniques to make these predictions was examined. Additionally, the importance of the dataset size on prediction accuracy and the dataset-proportioning method for developing predictive models were assessed. Both ANN and PLSR models predicted FFA levels and oleic acid concentrations with high accuracy, but PV and linoleic acid concentrations were predicted poorly. Changing the test-dataset proportioning method for the small dataset led to comparable R2test values by both ANN and PLSR in predicting FFA levels. Successful prediction of FFA levels could be explained partly by high variability, even in the dataset with the small number of samples. The study highlights the significance of factors like dataset size, test-dataset proportioning method, and model selection when predicting the quality attributes.</p