Relationship and correlation between antioxidant content and capacity,processing method and fruit colour of cactus pear fruit

Cactus pear fruit is a valuable source of antioxidants and could be an important functional ingredient in foods. Cultivars differ in fruit colour, which may indicate the presence of specific antioxidants. There is increased interest for cactus pear-derived products due to their potential nutraceutical effects, and determining antioxidant potential in processed foods is an important measure to ascertain the quality of a processed product. The aim of the study was to determine the relationship of fruit processing method and colour with antioxidant content and activity in fresh and processed cactus pear fruit. Antioxidant components (ascorbic acid, phenolic compounds, carotenes and betalains) and antioxidant activity (radical scavenging activity towards 2,2′-diphenyl-1-picrylhydrazyl and iron chelating capacity) were determined in fresh and processed (juiced, dried, preserved and chutney) fruits from four different coloured cultivars (purple, green, orange and pink). The highest antioxidant content and potential was found in purple (O. robusta cv Robusta) fruit products, attributed to the highest levels of betalains (1140.4 mg kg^?1). Orange fruit (O. ficus-indica) products had the second highest levels, attributed to ascorbic acid and phenolics. Betalains were highly retained in all processed products, while ascorbic acid was mostly retained in the processed products that involved minimal heat treatment. Carotene and phenolic compounds became more available for extraction during processing and showed higher levels after processing. Principal component analysis makes it possible to identify fruit colours of fresh and processed products, which were mostly associated with a specific antioxidant. In the PCA biplot, PC1 (47.93%) and PC2 (21.93%) explained 69.15% of the total variation: a processing method rather than colour-correlated products in terms of antioxidant content and potential. PCA indicated that fresh purple fruit was correlated with chelating activity and betalains, while orange fruit was clustered with phenolics, ascorbic acid, carotene and DPPH. For the processed fruit products, most were clustered together with chelating activity, DPPH and the antioxidants. Orange and pink dried products had high ascorbic acid, phenolics, carotene and DPPH values, while dried and fresh purple fruit had high betalain content and chelating activity.     

Far infrared and ultraviolet radiation as a combined method for surface pasteurization of black pepper seeds

This study presented the potential of far infrared (FIR) and ultraviolet (UVC) radiation for surface pasteurization of black pepper seeds. FIR treatment at different exposure times and temperatures was applied followed by constant UVC treatment with an intensity of 10.5 mW/cm² for 2 h. Then, the reduction on total mesophilic aerobic bacteria (TMAB) and mold-yeast contents were determined, and quality changes of the seeds were evaluated. TMAB of the seeds decreased to the target level of 10⁴ CFU/g after 4.7 and 3.5 min FIR treatment at 300 and 350 °C, respectively. Under given conditions, complete elimination for other microorganisms (TMY, Escherichia coli and Bacillus cereus) was also obtained while there were no significant changes in volatile oil and color. UVC however, alone or in combination with FIR, did not exhibit a significant reduction in TMAB content. Consequently, FIR treatment was suggested to be a promising method for the surface pasteurization of black pepper seeds.