The objective of this study was to assess the chemical, physical, morphological, crystalline and thermal properties of starch from two non-traditional vegetables, yam and taro. The analyses included proximate composition percent, amylose and mineral content, water absorption capacity, absolute density, morphological properties, X-ray diffractometry, thermal properties, pasting properties and infrared spectrum. The extracted starch exhibited a high purity level with low lipid, fiber and ash contents. The electron micrographs suggested that the taro starch granules were smaller than the yam starch granules. The results for the experimental conditions used in this study indicated that the studied starches differed, especially the amylose content, granule size and crystallinity degree and the pattern of the starches. Due to the high amylose content of yam starch, this type of starch can be used for film preparation, whereas the taro starch can be used as a fat substitute due to its small granule size.

Storing processed food products can cause alterations in their chemical compositions. Thus, the objective of this study was to evaluate carotenoid retention in the kernels of minimally processed normal and vitamin A precursor (proVA)-biofortified green corn ears that were packaged in polystyrene trays covered with commercial film or in multilayered polynylon packaging material and were stored. Throughout the storage period, the carotenoids were extracted from the corn kernels using organic solvents and were quantified using HPLC. A completely factorial design including three factors (cultivar, packaging and storage period) was applied for analysis. The green kernels of maize cultivars BRS1030 and BRS4104 exhibited similar carotenoid profiles, with zeaxanthin being the main carotenoid. Higher concentrations of the carotenoids lutein, β-cryptoxanthin, and β-carotene, the total carotenoids and the total vitamin A precursor carotenoids were detected in the green kernels of the biofortified BRS4104 maize. The packaging method did not affect carotenoid retention in the kernels of minimally processed green corn ears during the storage period.Index terms: Provitamin A; biofortification; packaging; storage. RESUMOO armazenamento de produtos alimentícios processados pode causar alterações na sua composição química. Sendo assim, objetivou-se, com este trabalho, determinar a retenção de carotenóides em grãos de milho verde normal e biofortificado com precursores de vitamina A, em espigas minimamente processadas, embaladas em bandeja de poliestireno com cobertura de filme comercial e embalagem multicamadas nylon poli ao longo do período de estocagem do produto. Os carotenóides foram extraídos dos grãos de milho verde em esquema sequencial de solventes orgânicos e quantificados por CLAE. O experimento foi planejado em delineamento inteiramente casualizado em esquema fatorial, constituído de três fatores (cultivar, embalagem, período de armazenamento). Os grãos verdes das cultivares de milho BRS1030 e BRS4104 apresentam semelhança no perfil de carotenóides, sendo zeaxantina o principal carotenoide presente nos grãos verdes desses materiais. Maiores concentrações dos carotenóides luteína, β-criptoxantina, β-caroteno, carotenóides totais e do total de carotenóides precursores de vitamina foram identificadas nos grãos verdes do milho biofortificado BRS4104. A retenção de carotenóides em grãos verdes de milho, durante o período de estocagem das espigas minimamente processadas, não foi influenciada pelos tipos de embalagens estudadas.Termos para indexação: Provitamina A; biofortificação; embalagem; armazenamento.

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Processed food products may undergo changes in chemical composition during processing, leading to potential losses in nutritional value. The objective of this study was to determine carotenoid retention in immature grains of normal corn (BRS1030) and corn biofortified (BRS4104) with vitamin A precursors subjected to different thermal treatments: cooking in a microwave, cooking in a pressure cooker, cooking in a pot with a lid and cooking in a pot without a lid. The experiment had a completely randomized design in a factorial scheme (cultivar and type of cooking). The carotenoids were extracted in a sequential organic solvent scheme and quantified by high-performance liquid chromatography (HPLC). The results were submitted to analysis of variance (ANOVA), and when significant, the means were compared using the least significant difference (LSD) test (p = 0.05). Despite cultivars, the concentrations of carotenoid vitamin A precursors and total carotenoids in the immature corn grains were reduced after cooking the ears in a microwave or in a pressure cooker. The best treatments for preserving carotenoids according to the conditions studied are cooking in a pot with a lid and in a pot without a lid.

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Eletromicrografias de varredura de polvilhos doce e azedo Eletromicrographs of sweet and sour sprinkles sweeping