Fruit quality and antioxidant capacity of six Thai mango cultivars

Improvements in the color, phytochemical, and antioxidant properties of frozen ripe mango pieces using calcium chloride dipping and chitosan coating

This study aimed to investigate the influences of a dipping/coating composed of calcium chloride (CaCl2 ) or chitosan on the quality of ripe mango pieces during frozen storage for 6 months. The fruits were dipped in solutions with concentrations of 0.5% and 1% for different times (15 or 30 min for CaCl2 and 1 or 15 min for chitosan). We found that treatment with 1% CaCl2 for 30 min significantly retarded the color changes with the highest L* (p < 0.05) and the lowest of b* and ∆E (p ≥ 0.05). Interestingly, treatment with 0.5% CaCl2 for 30 min significantly preserved the contents of total phenolics and total flavonoids and the antioxidant activities at values higher than the control levels, as determined by DPPH and ABTS assays (p < 0.05). Moreover, treatment with 0.5%-1% chitosan for 1 min effectively delayed the loss of moisture and weight. The results indicate that dipping in CaCl2 is an alternative simple food processing technique for improving the quality of ripe mango pieces during frozen storage that effectively delays the color changes and preserves the antioxidant content and activity. HIGHLIGHTS: The coating of frozen ripe mango pieces with CaCl2 and chitosan was first investigated. CaCl2 effectively retarded the color change during storage and after thawing. Chitosan effectively delayed the loss of moisture and weight of mango pulp. Coating with 0.5% CaCl2 for 30 min maintained the phytochemicals and antioxidant activities. Coating treatment can preserve mango qualities and could be commercialized with cost savings. PRACTICAL APPLICATION: The present article proposes a strategy that effectively delays the physicochemical changes and preserves the nutritional properties of mango fruit and could be commercialized with cost savings. A frozen mango can either be consumed (ready-to-eat frozen mango) or used as a food raw material.

Preparation of Methylcellulose Film-Based CO2 Indicator for Monitoring the Ripeness Quality of Mango Fruit cv. Nam Dok Mai Si Thong

Day-to-day advancements in food science and technology have increased. Indicators, especially biopolymer-incorporated organic dye indicators, are useful for monitoring the ripeness quality of agricultural fruit products. In this investigation, methylcellulose films—containing pH dye-based indicators that change color depending on the carbon dioxide (CO₂) levels—were prepared. The level of CO₂ on the inside of the packaging container indicated the ripeness of the fruit. Changes in the CO₂ level, caused by the ripeness metabolite during storage, altered the pH. The methylcellulose-based film contained pH-sensitive dyes (bromothymol blue and methyl red), which responded (through visible color change) to CO₂ levels produced by ripeness metabolites formed during respiration. The indicator solution and indicator label were monitored for their response to CO₂. In addition, a kinetic approach was used to correlate the response of the indicator label to the changes in mango ripeness. Color changes (the total color difference of a mixed pH dye-based indicator), correlated well with the CO₂ levels in mango fruit. In the ‘Nam Dok Mai Si Thong’ mango fruit model, the indicator response correlated with respiration patterns in real-time monitoring of ripeness at various constant temperatures. Based on the storage test, the indicator labels exhibited color changes from blue, through light bright green, to yellow, when exposed to CO₂ during storage time, confirming the minimal, half-ripe, and fully-ripe levels of mango fruit, respectively. The firmness and titratable acidity (TA) of the fruit decreased from 44.54 to 2.01 N, and 2.84 to 0.21%, respectively, whereas the soluble solid contents (SSC) increased from 10.70 to 18.26% when the fruit ripened. Overall, we believe that the application of prepared methylcellulose-based CO₂ indicator film can be helpful in monitoring the ripeness stage, or quality of, mango and other fruits, with the naked eye, in the food packaging system.

A novel colorimetric indicator for ethanol detection in preserved baby mangoes

A colorimetric indicator cube for use in smart packaging was designed and fabricated to detect ethanol produced by microbial fermentation in preserved baby mangoes. The presence and level of ethanol was indicated by color variations of the indicator cube, which consists of porous melamine foam (MF) that entraps an indicator solution of potassium dichromate and sulfuric acid. Within the packaging, the cube sits behind a gas-permeable membrane. The morphological structure of MF was studied by digital microscope and X-ray fluorescence analysis. In the optimal condition, the indicator cube exhibited distinct color changes from yellow to brown, green and blue over an ethanol concentration range from 0.25% to 5.0%. Color changes were clearly visible to the naked eye. The repeatability of the ethanol indicator cube was good and storage stability was maintained for up to 19 and 74 days at room and refrigeration temperatures, respectively. The smart packaging was applied to detect ethanol in preserved baby mangoes at different storage times.

Supercritical CO2 Extraction of Bioactive Compounds from Mango (Mangifera indica L.) Peel and Pulp

The potential of supercritical CO₂ (SC-CO₂) for the extraction of bioactive compounds from mango by-products was assessed. Carotenoid extraction was optimized using a design of experiments based on temperature (35, 55 and 70 °C), pressure (10 and 35 MPa) and co-solvent addition (0%, 10% and 20% of ethanol or acetone). Moreover, the co-extraction of phenolic acids, flavonoids and xanthonoids was evaluated in a subset of parameters. Finally, a comparison was made between SC-CO₂ and a two-step organic solvent extraction of the bioactive compounds from the pulp and peel fractions of two Ecuadorian varieties. The optimal extraction temperature was found to be dependent on the bioactive type, with phenolics requiring higher temperature than carotenoids. The optimal overall conditions, focused on maximal carotenoids recovery, were found to be 55 °C, 35 MPa and 20% of ethanol. The main carotenoid was β-carotene, while phenolics differed among the varieties. The bioactive content of the peel was up to 4.1-fold higher than in the pulp fraction. Higher antioxidant activity was found in the extracts obtained with organic solvents. SC-CO₂ is a promising technology for the isolation of valuable compounds from mango by-products.

The potential of Mangifera indica Linn. and Musa acuminata extracts to attenuate 4-hydroxyestradiol (4-OHE2 )-induced DNA oxidative damage in MCF-10A cells by upregulating detoxifying and antioxidant enzymes

Nowadays, there have been attempts to use phytochemicals in fruits to reduce the risk of suffering a given sickness. In this work, we studied the potential effects of mango (cultivar "Nam Dok Mai") and banana (cultivar "Khai") to attenuate DNA oxidative damage in MCF-10A cells induced by 4-hydroxyestradiol (4-OHE₂ ). The effects of mango extract (MNE) and banana extract (BKE) were comparable with three carotenoid compounds, β-carotene, lycopene, and lutein. The oxidative-induced DNA damage was evaluated by 8-hydroxy-2-deoxyguanosine (8-OHdG) reduction. 4-OHE₂ -induced DNA oxidative damage in MCF-10A cells showed a decrease in 8-OHdG formation when treated with MNE and BKE. Both fruit extracts also enabled the regaining production of Phase II detoxifying (GSTs and NQO1) and antioxidant (SOD, GPx, and CAT) enzymes during 4-OHE₂ -induced DNA oxidative damage in the MCF-10A cells when compared with the untreated control. These results indicate that MNE and BKE can exert potential mitigating effects against 4-OHE₂ -induced DNA oxidative damage in MCF-10A cells by enhancing the activities of detoxifying and antioxidant enzyme. PRACTICAL APPLICATIONS: Long-term exposure to estrogen increases the risk of sickness since oxidative stress via the estrogen pathway, leading to DNA damage. This study indicated that mango (cultivar "Nam Dok Mai") extract contains β-carotene and lycopene, while banana (cultivar "Khai") extract contains β-carotene and lutein, which act as natural antioxidants. Both fruit extracts have preventive properties against oxidative DNA damage and are potentially good supplements for women taking E₂ between HRT.

Impact of Preharvest and Postharvest on Color Changes during Convective Drying of Mangoes

The purpose of this study was to evaluate the impact of the harvest stage, ripening conditions and maturity on color changes of cv. ‘Cogshall’ and cv. ‘Kent’ variety mangoes during drying. A total of four harvests were undertaken, and the fruits were ripened at 20 and 35 °C for five different ripening times at each temperature. At each ripening time, mangoes were dried at 60 °C/30% RH/1.5 m/s for 5 h. A wide physico-chemical and color variability of fresh and dry pulp was created. The relationships according to the L*, H* and C* coordinates were established using mixed covariance regression models in relation to the above pre- and postharvest (preprocess) parameters. According to the L* coordinate results, browning during drying was not affected by the preprocess parameters. However, dried slices from mangoes ripened at 35 °C exhibited better retention of the initial chroma, and had a greater decrease in hue than dried slices from mangoes ripened at 20 °C. However, fresh mango color, successfully managed by the pre- and postharvest conditions, had more impact on dried mango color than the studied parameters. The preprocess parameters were effective levers for improving fresh mango color, and consequently dried mango color.

Carotenoid Biosynthesis and Plastid Development in Plants: The Role of Light

Light is an important cue that stimulates both plastid development and biosynthesis of carotenoids in plants. During photomorphogenesis or de-etiolation, photoreceptors are activated and molecular factors for carotenoid and chlorophyll biosynthesis are induced thereof. In fruits, light is absorbed by chloroplasts in the early stages of ripening, which allows a gradual synthesis of carotenoids in the peel and pulp with the onset of chromoplasts' development. In roots, only a fraction of light reaches this tissue, which is not required for carotenoid synthesis, but it is essential for root development. When exposed to light, roots start greening due to chloroplast development. However, the colored taproot of carrot grown underground presents a high carotenoid accumulation together with chromoplast development, similar to citrus fruits during ripening. Interestingly, total carotenoid levels decrease in carrots roots when illuminated and develop chloroplasts, similar to normal roots exposed to light. The recent findings of the effect of light quality upon the induction of molecular factors involved in carotenoid synthesis in leaves, fruit, and roots are discussed, aiming to propose consensus mechanisms in order to contribute to the understanding of carotenoid synthesis regulation by light in plants.

BY-PRODUCTS OF PROCESSING CAROB MOLASSES AS SOURCES OF DIETARY FIBRE AND POLYPHENOLS

Dietary fibre and polyphenols have been widely used to increase the functionality of some foods because of their potential  effects on human health. In this study, extraction of dietary fibre and polyphenols from pomace obtained as a by-product of processing carob molasses has been studied. The dietary fibre and polyphenol extracts were prepared separately. The amount of dietary fibre in the carob molasses pomace was evaluated with two assays: the Association of Official  Analytical Chemists’ enzymatic-gravimetric method and the enzymatic-chemical method. The methods were compared, each having been preceded by conventional extraction and ultrasound-assisted extraction of carob  molasses pomace. It has been found that when the enzymatic-gravimetric method and the ultrasound-assisted extraction method were used, the total dietary fibre contents were significantly higher than after using the enzymatic-chemical method and the conventional extraction method. Conventional extraction of polyphenols from carob molasses pomace has shown a relatively higher polyphenol content and antioxidant activity than ultrasound-assisted extraction. Ultrasound-assisted extraction  took  less time than conventional extraction did. The polyphenol profile was characterised by means of a high-performance liquid-chromatography diode array detector using 10 phenolic standards. Six compounds, i.e. caffeic, syringic, -epicatechin, trans-cinnamic  acid,  myricetin,  and naringin were determined with the high-performance liquid chromatography-diode array detector using both conventional extraction and the ultrasound-assisted extraction. Our results suggest that carob molasses pomace can be used to prepare low-calorie, high-fibre, and antioxidant-rich foods, nutraceuticals, and pharmaceuticals.

Enrichment of Mango Fruit Leathers with Natal Plum (Carissa macrocarpa) Improves Their Phytochemical Content and Antioxidant Properties

Natal plum fruit (Carissa macrocarpa) is indigenous to South Africa and a rich source of cyanidin derivatives. Indigenous fruits play a major role in food diversification and sustaining food security in the Southern African region. Agro-processing of indigenous are practiced adopted by the rural African communities in order to reduce the postharvest wastage of fruit commodities. In the current study, Natal plum was added to mango pulp at different ratios (mango and Natal plum (5:1, 3:1, 2:1)) to develop a healthy-functional snack (fruit leather). The effects of added Natal plum on the availability of antioxidant constituents and in vitro antioxidant properties of a mango-based fruit leather were evaluated by comparing with mango fruit leather. Fruit leather containing mango and Natal plum (2:1) retained the highest content of cyanidin-3-O-glucoside chloride, cyanidin- 3-O-β-sambubioside, epicatechin, apigenin, kaempferol, luteolin, quercetin-3-O-rhamnosyl glucoside, catechin, quinic, and chlorogenic acids, and in vitro antioxidant activity. Proximate analysis showed that 100 g of fruit leather (2:1) contained 63.51 g carbohydrate, 40.85 g total sugar, 0.36 g fat, and 269.88 cal. Therefore, enrichment of mango fruit leather with Natal plum (2:1) increases its phytochemical content and dietary phytochemical intake, especially for school children and adolescents.