No abstract

Previous study revealed that hot water treatment (HT) at 50°C for 30 min of whole mango fruit before fresh cut process can maintain the quality of fresh cut mango. In this study the combination of HT before fresh cut process and calcium ascorbate dip at post-fresh cut process was investigated. Ripe mangoes cv. Nam Dok Mai were dipped into hot water (HT, 50°C for 30 min) then mangoes were peeled and cut into fresh cut mangoes. They were dipped into 2% w/v aqueous calcium ascorbate (CaAs). Non-calcium treated fresh cut mango was used as the control set. Both of CaAs and control treatment were stored at 4 °C for 6 days. Changes in color of fresh cut surface mango, browning occurrence, sensory acceptance was evaluated. Polyphenol oxidase (PPO) activity was measured. CaAs treatment maintained color changes expressed as L* and Hue angle compared to control (HT). CaAs dips inhibited PPO activity resulting in browning reduction and high acceptance of sensory evaluation. The combination of HT of whole fruit and CaAs dips of fresh cut mango extended the overall quality to 6 days compared to 3 days for mango heated with HT but not dipped into CaAs. CaAs also showed the higher firmness than control sample. The combination of HT at 50°C for 30 min of whole fruit followed by 2% CaAs dip of fresh cut mango can preserve the quality of fresh cut mango during storage.

Chlorophyll and carotenoid are the main pigments that are responsible for coloration of citrus fruit. The changes in their contents are related to the development stage in citrus fruit. During fruit maturation, carotenoids are massively accumulated in the flavedo and juice sacs, while the chlorophyll contents decreased rapidly. In contrast, the increase of chlorophyll content and decrease of carotenoid contents are observed in the fruit during regreening process. In addition, plant hormones and environmental conditions play important roles in the regulation of color development and the changes of chlorophyll and carotenoid contents in citrus fruit. In this review, we summarized the changes in chlorophyll and carotenoid contents in the flavedo and juice sacs of citrus fruit during fruit maturation and regreening process. Current understanding on the molecular mechanisms that regulated the chlorophyll and carotenoid metabolisms in citrus fruit are discussed. Moreover, the effects of plant hormones and environmental conditions on chlorophyll and carotenoid accumulation are also presented in this review.