Copper(II) and Sulfur Dioxide in Chardonnay Juice and Shiraz Must: Impact on Volatile Aroma Compounds and Cu Forms in Wine

This work outlines the influence of Cu(II) and SO2 concentrations in Chardonnay juice or Shiraz must on the respective wine composition. Analyses were conducted pre- and post-fermentation, after cold stabilization, after bentonite treatment (Chardonnay only), at bottling, and 15 months after bottling. The quantification of total Cu was conducted by inductively coupled plasma optical emission spectrometry and free Cu by stripping potentiometry. Low molecular weight sulfur compounds, volatile aldehyde compounds, and general volatile compounds, including esters and terpenes, were quantified with gas-chromatography- or liquid-chromatography-QQQ-mass spectrometry. For Chardonnay, increased Cu concentration in the juice resulted in higher concentrations of Cu in the respective wine, while Shiraz wines showed no significant difference. Increased Cu addition to Chardonnay juice also produced significantly higher concentrations of H2S, 3-methylbutanal, and methional, but lower concentrations of methanethiol and phenylacetaldehyde, while SO2 addition increased 3-methylbutanal and phenylacetaldehyde, and decreased methanethiol production from post-fermentation to post-bottle aging. For the Shiraz, SO2 led to higher concentrations of H2S, and both SO2 and Cu addition increased the concentrations of hexanal, 3-methylbutanal, and phenylacetaldehyde in wine, but this effect diminished after cold stabilization. This study shows that SO2 and Cu in grape juice/must can have long-term implications for wine composition.

Eu(iii)-functionalized ZnO@MOF heterostructures: integration of pre-concentration and efficient charge transfer for the fabrication of a ppb-level sensing platform for volatile aldehyde gases in vehicles

Eu(iii)-functionalized ZnO@MOF heterostructures have been fabricated and performed as an improved ppb-level sensing platform for volatile aldehyde gases in vehicles by pre-concentration and efficient charge transfer.

Seed invigoration treatments in different seed sizes of sunflower (Helianthus annuus L.) for maintenance of vigour, viability and yield potential

Pre-storage dry treatment of freshly harvested (high-vigour) sunflower (Helianthus annuus L.) seeds in different seed sizes (viz. composite, large, medium and small) with red chilli powder (@ 1 g/kg of seed) and bleaching powder (@ 2g/kg of seed) significantly slowed down seed deterioration under natural ageing conditions and increased field performance and productivity along with reduced leakage of electrolytes, lower volatile aldehyde production with higher dehydrogenase enzyme activity over their respective untreated control. Among the seed sizes, large seeds showed higher post-storage germinability as well as field performance and productivity than the other categories of seeds. Interaction effects were non-significant which indicated that the treatment effects are independent of seed sizes. On the basis of the present investigation, pre-storage dry treatments in large sized seeds with red chilli powder and bleaching powder may be suggested for improved germinability and yield potential of stored high-vigour sunflower seeds.

Optimal Ripeness Stage for Processing ‘Kent’ Mangoes into Fresh-cut Slices

The optimal ripeness stage for processing and marketing fresh-cut mangoes (Mangifera indica ‘Kent’) with best quality and maximum shelf life was determined. The initial ripeness stage selection was based on whole fruit firmness because this quality attribute was more reliable in predicting fresh-cut shelf life than flesh color or soluble solids content (SSC). Overall, the visual quality deteriorated differently and at different rates among ripeness stages. The shelf life, based on subjective visual evaluation, was 10, 7, and 5 days for ripeness stages corresponding to an average flesh firmness of 35, 30, and 25 N, respectively, and was mainly limited by desiccation and development of off-odor for the two firmer ripeness stages or symptoms of edge tissue damage and spoilage for the least firm stage. The slices from fruit with the highest initial firmness remained firmer during storage, had the lowest pH and SSC to titratable acidity (TA) ratio, and had the highest contents of volatile ketones and esters. The softest slices had the highest pH, SSC:TA ratio, and total ascorbic acid (TAA) content, as well as the lowest TA and highest volatile aldehyde and alcohol contents. Intermediate firmness slices had intermediate pH, SSC:TA ratio, color, and TAA content. Also, they had less volatile alcohols and aldehydes than slices from riper fruit but had similar content of esters as slices from the less ripe fruit. Therefore, based on the results from this study, an initial firmness of 30 N is recommended to process mangoes into fresh-cut slices because it assures the best quality and maximum shelf life based on textural, visual, and compositional attributes.

Effect of MAP on Quality of Rice for Super-Long-Term

In this study, effects of Modified Atmosphere (MA) packaging on the quality of rice after a long term storage at room temperature have been investigated. PVC films with different thicknesses and woven bag were used as the package materials for rice samples. Results showed that MA packaging had a significant effect on the quality of the rice. After an extended period of storage, the rice in woven bag showed most severe quality deterioration compared to those stored in PVC packages. Rice packed in 0.05 mm PVC film package has the lowest value of total acid among all samples. The increase of fatty acid content in rice packed in 0.03 mm film, 0.05 mm film, 0.08 mm film and 0.12 mm film was 38.58 mg KOH/100g, 18.96 mg KOH/100g, 26.83 mg KOH/100g and 32.64 mg KOH/100g, respectively. The volatile aldehyde components accumulated in the stored rice are mainly acetaldehyde, valeraldehyde and hexanal. Small package with a MA has obvious benefits in regulating the metabolism and accumulation of volatile aldehyde components in the rice. Rice samples stored in a package of 0.05mm film had the lowest value of volatile aldehyde, while those in 0.03mm film had the highest value. This study suggests that MA packaging with a PVC film of 0.05 mm shows the best effects in maintaining the quality of rice after an extended period of storage (3 to 5 years).