The objective of this work was to quantify the total phenolic content (TPC) and total antioxidant activity (TAA) of fruit from Brazilian genotypes of feijoa (Acca sellowiana). Skin and flesh tissues of the fruit were evaluated for the Alcântara, Helena, Mattos, and Nonante cultivars, and for the 2316 accession. TPC and TAA were both assessed in aqueous and hydroalcoholic extracts, and TAA was assayed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] methods. The TPC values, for aqueous extracts of the skin and flesh tissues, were 114.9 and 88.3 mg gallic acid equivalent (GAE) per 100 g fresh weight (FW), respectively. The corresponding values for TAA determined by the DPPH method, the skin and flesh tissues, given as EC₅₀ (substrate concentration which leads to 50% reduction of the DPPH), were 10.7 and 39.7 mg FW per g DPPH, respectively; and, by the ABTS method, the TAA values were 12.01 and 8.33 μmol L^-1 Trolox per g FW, respectively. The greatest values for TPC and TAA were obtained for 'Mattos' and 'Nonante', in the skin, and for 'Nonante' and accession 2316, in the flesh. Feijoa fruit has important functional value, particularly in the skin, characterized by high TPC and TAA.

The objective of this work was to evaluate the effect of rosemary, cinnamon, citronella grass, and clove essential oils on the in vitro growth of Penicillium expansum, on the diameter of blue mold lesions, and on the physical and chemical attributes of 'Fuji' apples stored under refrigeration for different periods of time. The compositions of the essential oils were determined, and their effects on the growth inhibition, number, and viability of fungal spores in vitro were evaluated at 0, 100, and 1,000 μL L^-1 oil concentrations. At postharvest, evaluations were performed for fruit treated with 0, 50, 100, and 500 μL L^-1 essential oil and kept under refrigeration for 30 days, and for fruit treated with 0, 100, and 500 μL L^-1 oil and kept under refrigeration for two days. The essential oils - eucalyptol (rosemary), eugenol (cinnamon), citronellal (citronella), and eugenol (clove) - reduce the growth, number, and viability of P. expansum spores 24 hours after the induction to germination, as well as the diameter of blue mold lesions in apples, except for citronella oil at 500 μL L^-1 after 30 days of cold storage. There are no changes in the physicochemical attributes of apples, treated with different concentrations of the oils after refrigeration for five months, followed by seven days at room temperature.

Avaliou-se a viabilidade de utilização de um colorímetro, como alternativa à utilização de medidor de clorofila, para a quantificação não destrutiva de clorofilas em folhas. Folhas de couve "Manteiga" e batata "Ágata", com tonalidades variando de verde amarelado (clorótica) a verde escuro, foram avaliadas individualmente com um medidor de clorofila (Minolta SPAD-502) e um colorímetro (Minolta CR-400, no espaço de cores L, C e hº), seguido de quantificações destrutivas de clorofilas a, b e totais. Os valores de leitura do medidor de clorofila e da relação hº/(LxC) do colorímetro aumentaram com o incremento nos teores de clorofilas nas folhas em couve e batata. Os modelos ajustados entre teores de clorofilas e as leituras do medidor de clorofila e da relação hº/(LxC) do colorímetro apresentaram valores similares de R², em ambas as espécies. Os resultados obtidos demonstram que o colorímetro é uma alternativa viável na avaliação não destrutiva do teor de clorofilas (µg cm-2 de folha), especialmente de clorofilas a e totais. Para tanto, os valores da relação hº/(LxC) do colorímetro devem ser calibrados com a extração de clorofilas nas folhas da espécie e genótipo de interesse.

This study aims to evaluate the effect of nitric oxide (NO) treatment under controlled atmosphere (CA) on quality of ‘Laetitia’ plums, mainly on internal browning. The experiment followed a completely randomized design, with five repetitions and a 25-fruit experimental unit. The evaluated treatments were: control (no NO); NO at 2 μL L⁻¹ (low dose) applied every 5 days of storage; NO at 5 μL L⁻¹ (medium dose) applied every 5 days of CA storage; and NO at 10 μL L⁻¹ (high dose) applied only at the beginning of CA storage. The treatments with NO in CA storage did not delay the loss of flesh firmness and compression force of the fruit. Treatments with NO reduced ethylene production and respiratory rates and delayed the skin color evolution, especially when applied at medium dose every 5 days of CA storage and high dose at the beginning of CA storage. The treatment with low dose of NO every 5 days of CA storage was the most effective to reduce the internal browning of ‘Laetitia’ plums.

The objective of this work was to evaluate the physicochemical attributes and vitamin C contents of fruits of five Brazilian genotypes of feijoa (Acca sellowiana), at harvest and after cold storage. The Alcântara, Mattos, Helena, and Nonante cultivars, as well as accession 2316, were studied. The assessed attributes were: fresh mass loss, titratable acidity, soluble solids contents, soluble solids contents/titratable acidity ratio, pH, skin and flesh color, texture, and vitamin C contents (skin and flesh). After storage, there were reductions of 2.9% in soluble solids contents, of 32.2% in titratable acidity, and of approximately 85% in texture attributes, besides increases of 36.3% in the soluble solids contents/titratable acidity ratio and of 21.7% in the pH of fruits. The vitamin C content in the skin was higher than that in the flesh, and increased in both skin and flesh after storage. 'Alcântara' fruits have the highest contents of vitamin C in the skin and flesh. Fruits of 'Nonante' and 'Mattos' show better preservation of the texture attributes, and fruits of 'Nonante', the lowest levels of flesh browning during storage.