Changes in the quality of jaboticaba fruit (Myriciaria jaboticaba (Vell) Berg. cv. Sabará) stored under different oxygen concentrations

BACKGROUND: Jaboticaba (Myriciaria jaboticaba (Vell) Berg.) is a highly perishable Brazilian berry with a shelf life of only 2 days under ambient conditions. Low temperatures and controlled atmosphere (CA) have been used to extend the shelf life of perishable fruit. Thus the aim of this study was to determine the effect of CA with varying concentrations of oxygen (1, 5, 10, 15 and 21kPa) during cold storage (12.5 °C) of ‘Sabará’ jaboticaba fruit. RESULTS: Atmospheres with lower oxygen concentrations (1 and 5 kPa O₂) significantly reduced jaboticaba respiration rate. Fruit stored under these conditions had higher L* values, and titratable acidity (TA), and lower ratios of soluble solids content (SSC)/TA. However, at the lowest concentration of oxygen (1 kPa O₂), firmness decreased markedly compared to fruits stored at higher O₂ levels (P < 0.05). After only 2 days of storage at ambient temperature jaboticaba received a score of 1.6 (dislike strongly ? 1) compared to fruit stored under CA, which scored 7.4 (like moderately ? 7). After 9 days of storage, fruit from all treatments remained above the limit of acceptability (score 5) and were rated as 6.2. With respect to appearance, statistical differences between treatments were not observed. The total anthocyanin content was not affected by oxygen concentration but decreased 40.4% during CA storage. CONCLUSION: 'Sabará' jaboticaba fruit can be satisfactorily stored under atmospheres containing 5‐21 kPa O₂ at 12.5 °C for up to 6 days. Copyright © 2011 Society of Chemical Industry     

Evaluation of Aloe arborescens gel as new coating to maintain the organoleptic and functional properties of strawberry (Fragaria × ananassa cv. Cadonga) fruits

Strawberries (Fragaria × ananassa cv. Cadonga) are highly perishable fruits with a storage life, which may be less than a week. In this study, Aloe arborescens gel was used as post-harvest treatment in order to maintain strawberry quality. Strawberries coated with edible A. arborescens gel were packaged in a polypropylene box and stored. Fruit titratable acidity, pH, soluble solid content, ascorbic acid, total phenols, total flavonoids, total anthocyanins and antioxidant activity evaluated by two different tests (DPPH and ABTS) were measured during 14 days of storage. Significant differences were found (P < 0.05) for the samples treated with A. arborescens compared to the control. During conservation, use of Aloe gel maintained lower values for total soluble solids, a higher concentration of total phenols and ascorbic acid, and a better antioxidant activity when compared to the control. The anthocyanin content remained largely unchanged throughout, in all compared samples.     

Identification and quantification of major phenolic compounds from mango (Mangifera indica, cv. Ataulfo) fruit by HPLC–DAD–MS/MS-ESI and their individual contribution to the antioxidant activity during ripening

Mango (Mangifera indica L.) is an economically important fruit throughout the world. ‘Ataulfo’ mango, a leading cultivar in Mexico, has the highest content of phenolic compounds among several commercial varieties of mango. However, the individual identification and antioxidant contribution of these phenols during ripening of mango fruit is unknown. Qualitative and quantitative analysis of the major phenolic compounds found in ‘Ataulfo’ mango fruit pulp was conducted in four stages of ripeness, using high-performance liquid chromatography coupled to mass spectrometry. The antioxidant contribution of each of the major phenolic compounds was calculated. The major compounds identified were chlorogenic acid (28–301 mg/100 g DW), gallic acid (94.6–98.7 mg/100 g DW), vanillic acid (16.9–24.4 mg/100 g DW), and protocatechuic acid (0.48–1.1 mg/100 g DW). The antioxidant contribution of the four phenolic acids increased during ripening. Gallic acid accounted for the highest contribution (39% maximum value), followed by chlorogenic acid (21% maximum value). This could indicate that these phenolic compounds may have an important role in the antioxidant metabolism in ‘Ataulfo’ mango fruit during ripening, and promoting health benefits to consumers.     

The impact of chitosan film or chitosan/chitosan–epigallocatechin gallate conjugate composite film on the quality changes of Asian sea bass (Lates calcarifer) slices stored in air or under vacuum packaging

Quality and shelf-life of Asian sea bass slices (ASBS) wrapped with chitosan (CS)/CS–epigallocatechin gallate (CE) conjugate composite or CS films and packaged in air or under vacuum during storage at 4 °C were studied. Total viable count was less than permissible limit (6 log·CFU g⁻¹ sample) for ASBS wrapped with CS/CE conjugate composite film under vacuum (ASBS-COMP-VP) after 18 days. Moreover, lower microbial proliferation and volatile base contents were attained in ASBS-COMP-VP sample than other samples during the storage (P < 0.05). At the end of storage, ASBS-COMP-VP sample had lower lipid oxidation than those wrapped with CS film (P < 0.05). Polyunsaturated fatty acid content of ASBS-COMP-VP was retained at higher content at day 18. Therefore, ASBS-COMP-VP had the enhanced shelf-life with high acceptability up to 18 days at 4 °C, while ASBS wrapped with CS film and packaged in air or under vacuum had the shelf-life of 9 and 12 days, respectively.     

The role of 2-hydroxypropanal in the biosynthesis of 2,5-dimethyl-4-hydroxy-2H-furan-3-one in strawberry (Fragaria × ananassa,cv. Elsanta) callus cultures

2-Hydroxypropanal was synthesized utilising a new approach via the Curtius rearrangement, which has the great advantage that the only co-product is ammonium chloride. 2-Hydroxypropanal was, without isolation, fed in situ to strawberry callus cultures in order to study the biosynthesis of 2,5-dimethyl-4-hydroxy-2H-furan-3-one. The high levels of the furanone obtained suggest that 2-hydroxy-propanal is a key precursor of 2,5-dimethyl-4-hydroxy-2H-furan-3-one in strawberry.     

Bacterial formation of tooeleite and mixed arsenic(III) or arsenic(V)-iron(III) gels in the Carnoulès acid mine drainage,France. A XANES,XRD, and SEM study

The oxidation of Fe(II) in acid mine drainage (AMD) leads to the precipitation of Fe(III) compounds which may incorporate toxic elements, such as arsenic (As), within their structure or adsorb them at their surface, thus limiting their mobility. The present work provides evidence for spatial and seasonal variations of microbial activity that influence arsenite oxidation and As immobilization in the heavily contaminated AMD from the Carnoulès mine, Gard, France ([As III] = 80 to 280 mg x L(-1) in the acidic spring draining the waste-pile). In the first tens of meters of the AMD, the rapid oxidation of Fe(II) leads to the coprecipitation of large amounts of As with Fe(III) in bacterial mats. XRD, XANES, and SEM analyses of sediments and stromatolite samples revealed the unusual formation of As(III)-rich compounds, especially nanocrystalline tooeleite, Fe6(AsO3)4(SO4)(OH)4 x 4H2O, a rare ferric arsenite sulfate oxy-hydroxide mineral, together with XRD-amorphous mixed As(III)/As(V)-Fe(III) oxy-hydroxide compounds. In the wet season, the suspended sediments of the upstream zone essentially consist of tooeleite associated with am-As(III)-Fe(III) oxy-hydroxides, while am-As(V)-Fe(III) oxy-hydroxides, having As:Fe molar ratios as high as 0.6-0.8, dominate in the dry season. Comparing natural and bioassay samples revealed that the formation of As(III)-rich compounds in the wet season may be related to the metabolic activity of bacterial strains able to oxidize Fe(II) but not As(III). One of these strains, having an Acidithiobacillus ferrooxidans genotype, has been isolated from the Carnoulès AMD. In contrast, the formation of As(V)-rich compounds in the dry season can be related to both biotic and abiotic oxidation of As(III) to As(V). Some Thiomonas strains isolated from the Carnoulès AMD were shown to be able to catalyze the oxidation of As(III) to As(V) in solution. Therefore, they can promote the formation of mixed As(V)-Fe(III) oxy-hydroxides, provided enough Fe(II) oxidizes. These results yield a better understanding of natural processes at this site and may help in designing efficient As-removal processes.