RESUMEN
Antifreeze proteins (AFPs) have the ability to modify ice crystal growth and thus there is great interest in identifying new sources of these compounds. All extracts of cold acclimated leaves of Drimys angustifolia, obtained using different buffers, inhibited recrystallization and they presented similar SDS-PAGE profiles, with bands close to 20 and 37â¯kDa. The extract obtained using Tris-HCl/DDT buffer (pH 8) was used in the pre-treatment of frozen star fruit (Averrhoa carambola) by immersion or vacuum infiltration. The treatments did not affect the titratable acidity, pH, soluble solids, ascorbic acid content and colour. However, only star fruits that were vacuum infiltrated with AFPs retained their drip loss constant after 15â¯days. Moreover, with this treatment the star fruit firmness was maintained on thawing after 60â¯days of storage. The vacuum infiltration of Drimys angustifolia AFPs into the star fruit allowed an initial cryoprotection, indicating that the application of AFPs can increase the quality of frozen star fruit.
Asunto(s)
Proteínas Anticongelantes/química , Averrhoa/química , Drimys/metabolismo , Almacenamiento de Alimentos/métodos , Hojas de la Planta/metabolismo , Proteínas Anticongelantes/aislamiento & purificación , Cristalización , Congelación , Frutas/química , Extractos Vegetales/metabolismo , VacioRESUMEN
The green coloring is the first characteristic in mate tea (chimarrão). Mate producers perform the sapeco process by rapidly passing the leaves through flames. It has been proven that this procedure leads to high energy consumption and also to excessive exposure of the raw material to heat. In this present work, the effect of sapeco on the inactivation of peroxidase, the color, and degradation of the chlorophyll in mate was evaluated by performing the sapeco procedure in a conveyor oven, without any direct contact with the flames. The mate processed in a conveyor oven was compared with mate processed in mate factories. Inactivation of peroxidase showed that sapeco performed in a conveyor oven at 255 ºC for 20 s can replace the traditional process of the industrial sapeco. This time/temperature binomial is significantly important for the green coloring and the minimization of chlorophyll degradation, besides representing a significant reduction in the temperature traditionally applied in the industrial sapeco of mate.
Asunto(s)
Clorofila/análisis , Manipulación de Alimentos , Almacenamiento de Alimentos , Ilex paraguariensis/química , Peroxidasas/metabolismo , Pigmentación , Proteínas de Plantas/metabolismo , Bebidas/análisis , Brasil , Dieta/etnología , Estabilidad de Enzimas , Calor , Ilex paraguariensis/enzimología , Hojas de la Planta/química , Hojas de la Planta/enzimología , Tallos de la Planta/química , Tallos de la Planta/enzimología , Factores de TiempoRESUMEN
Changes in the contents of carotenoids and their true retentions (% TR) during the production of puree of Cucurbita moschata 'Menina Brasileira' and of Cucurbita maxima 'Exposição' pumpkins and the stability of such compounds during 180days of storage were monitored by liquid chromatography coupled with a photodiode array detector. Cooking caused higher losses than commercial sterilisation. High losses of xanthophylls such as lutein and violaxanthin were noted during processing and storage of pumpkin puree. Such losses show the low stability of these compounds. The major carotenoids, pro-vitamin A carotenes, namely, α-carotene and all-trans-ß-carotene for C. moschata 'Menina Brasileira' and all-trans-ß-carotene for C. maxima 'Exposição' obtained high retentions (>75%) after processing. A slight degree of isomerisation of ß-carotene was noted in the puree samples, but with low concentrations of cis-isomers. Storage for 180days did not significantly affect (P⩽0.05) the concentrations of these carotenoids.