Predicting the quality attributes related to geographical growing regions in red-fleshed kiwifruit by data fusion of electronic nose and computer vision systems.

The ability of a data fusion system composed of a computer vision system (CVS) and an electronic nose (e-nose) was evaluated to predict key physiochemical attributes and distinguish red-fleshed kiwifruit produced in three distinct regions in northern Iran. Color and morphological features from whole and middle-cut kiwifruits, along with the maximum responses of the 13 metal oxide semiconductor (MOS) sensors of an e-nose system, were used as inputs to the data fusion system. Principal component analysis (PCA) revealed that the first two principal components (PCs) extracted from the e-nose features could effectively differentiate kiwifruit samples from different regions. The PCA-SVM algorithm achieved a 93.33% classification rate for kiwifruits from three regions based on data from individual e-nose and CVS. Data fusion increased the classification rate of the SVM model to 100% and improved the performance of Support Vector Regression (SVR) for predicting physiochemical indices of kiwifruits compared to individual systems. The data fusion-based PCA-SVR models achieved validation R2 values ranging from 90.17% for the Brix-Acid Ratio (BAR) to 98.57% for pH prediction. These results demonstrate the high potential of fusing artificial visual and olfactory systems for quality monitoring and identifying the geographical growing regions of kiwifruits.

Effect of different coatings on post-harvest quality and bioactive compounds of pomegranate (Punica granatum L.) fruits.

The effect of three different coatings; resin wax (Britex Ti), carnauba wax (Xedasol M14), and chitosan (1 and 2 % w/v) on postharvest quality of pomegranate fruits were investigated. Fruits quality characteristics and bioactive compounds were evaluated during 40, 80 and 120 days storage at 4.5 °C and 3 additional days at 20 °C. The results showed that uncoated fruits showed higher respiration rate, weight loss, L* and b* values of arils, total soluble solids (TSS)/titratable acidity (TA), and pH than coated fruits during storage. Coating treatments could delay declining TSS and TA percent, a* value of arils, as well as bioactive compounds such as total phenolics, flavonoids and anthocyanins content and antioxidant activity. The coated fruits with commercial resin and carnauba waxes showed significantly lower respiration rate and weight loss than other treatments, however carnauba wax could maintain considerably higher fruits quality and bioactive compounds than other coating treatments. The results suggested that postharvest application of carnauba wax have a potential to extend storage life of pomegranate fruits by reducing respiration rate, water loss and maintaining fruit quality.

The arils characterization of five different pomegranate (Punica granatum) genotypes stored after minimal processing technology.

In this study, the quality of minimally processed different Iranian pomegranate genotypes was investigated during storage at 4 °C for 14 days. The results showed that at the end of storage time, the lowest microbial count was found on the arils of "Torsh Syabe Lorestan" genotype. There was a significant difference in titratable acidity, total soluble solids, total anthocyanin, catechin, and quercetin content in most genotypes after 14-day cold storage; while no difference was found between studied genotypes in antioxidant capacity, total phenolic, and flavonoid content. In general, total phenolic content and antioxidant capacity of pomegranate arils gradually decreased over storage time. Diphenolase activity of polyphenol oxidase (PPO) enzyme with dopamine hydrochloride substrate and peroxidase (POD) decreased over storage time, whereas diphenolase activity of PPO with pyrocatechol substrate significantly increased. The lowest diphenolase activity with dopamine hydrochloride and pyrocatechol substrates, as well as POD activity was found in Torsh Syabe Lorestan. The results suggested that the genotype of Torsh Syabe Lorestan, which showed the lowest microbial count on the arils and enzymes, could be more appropriate for minimal processing technology.

Effect of chitosan coating on maintenance of aril quality, microbial population and PPO activity of pomegranate (Punica granatum L. cv. Tarom) at cold storage temperature.

BACKGROUND: Chitosan edible coating was used in an attempt to extend the storage life of pomegranate arils during 12 days at 4 °C. Prior to storage, treated arils were dipped in 0.25, 0.5 and 1% (w/v) chitosan aqueous solutions and 1% (v/v) acetic acid for 1 min, while control arils were dipped in distilled water with 1% (v/v) acetic acid. RESULTS: Chitosan coating inhibited bacterial and fungal growth on the surface of arils. The water content of arils coated with 0.5 and 1% chitosan was maintained during 12 days of storage. Chitosan reduced the increase in total soluble solids (TSS) and titratable acidity (TA) of arils during storage. The lowest TSS and TA were detected in arils coated with 0.5 and 1% chitosan, which maintained the highest TSS/TA ratio after 12 days of storage. In contrast, application of chitosan delayed the decrease in total phenolics, total anthocyanins and antioxidant capacity during storage. The results also showed that chitosan coating suppressed the monophenolase activity of polyphenol oxidase (PPO) with pyrogallol substrate and the diphenolase activity of PPO with dopamine hydrochloride substrate, but the diphenolase activity of PPO with pyrocatechol substrate increased during storage. CONCLUSION: The results suggest that chitosan coating has the potential to extend the storage life of pomegranate arils by reducing the microbial population on their surface.