EFFECTS of CONTROLLED ATMOSPHERE ON QUALITY of MINIMALLY PROCESSED APPLE (cv. JONAGORED)

Controlled atmosphere (2% O₂+ 4% to 12% CO₂) storage was found to be advantageous over air storage in terms of overall preservation of fresh-cut apple (cv. Jonagored). After 3 days, CA-stored apple cubes were firmer, showed better color and higher content of fructose and soluble solids content than air-stored cubes. In relation to color preservation this benefit was increased when CO₂ in the atmosphere was increased to 12% CO₂. Controlled atmosphere storage showed no advantage over air storage in relation to sensory evaluation of firmness and flavor.     

INFLUENCE of REACTION CONDITIONS ON the FORMATION of NONDIALYZABLE MELANOIDINES FROM D-FRUCTOSE and GLYCINE

The influence of the water content, molar ratio of reagents, time and temperature on the formation of nondialyzable melanoidines of the model system D-fructose-glycine has been studied.
The rate constants of the reaction for molar ratios 2.5:1, 1:1, 1:2.5 have been calculated to be (2.38 ± 0.17) x 10⁻⁵ S⁻¹, (3.94 ± 0.28) x 10⁻⁵ S⁻¹ and (5.11 ± 0.36) x 10⁻⁵ S⁻¹, respectively.
The activation energy has been determined (105.0 ± 3.6) kJ/mol and (74.6 ± 7.1) kJ/mol for molar ratios 2.5:1 and 1:2.5, respectively.     

Suitability of pre‐dawn and stem water potential as indicators of vineyard water status in cv. Tempranillo

Background and Aims: Irrigation management requires the collection of up‐to‐date information that allow growers to make rapid decisions, water potential being one of the most used parameters in irrigation scheduling. The goal of this research was to determine whether predawn (Ψpd) and stem (Ψs) water potential can be used equally well, quantifying the effect external factors have on the relationship between them. Methods and Results: Ψpd, mid‐morning (Ψs‐m) and noon (Ψs‐n) stem water potential were measured at seven cv. Tempranillo vineyards. Climatic conditions, vine growth and fruit load affected daily water potential dynamics. A greater decline of Ψs occurred when temperatures were higher and there was no dew formation, as well as under larger canopies and fruit load. While the relative impact of these variables on water potential was not particularly high, it was by no means negligible. Conclusions: Data collected in this study did not favour Ψpd, Ψs‐m or Ψs‐n as a preferred measure to evaluate plant water status. It is important to remark that similar Ψpd values do not necessarily indicate the same level of deficit, and that similar Ψs values do not always mean similar water availability. Therefore, a straightforward interpretation of Ψpd and Ψs can sometimes be misleading. Significance of the Study: The results obtained provide significant explanation to the lack of agreement in the literature regarding the most suitable time to measure water potential. Vineyard managers and scientists should select it according to the level of stress expected, climatic conditions and irrigation frequency.     

APPLICATION OF MULTIVARIATE STATISTICAL METHODS TO DIFFERENTIATION OF RUM AGED IN TWO TYPES OF OAK BARRELS

Multivariate statistical methods have been applied to analytical data for 14 major volatile compounds collected from various rum samples, in order to differentiate rums aged in two types of oak vessels, hogshead and pipe.     

ISOLATION AND CHARACTERIZATION OF MELANOIDINES FROM MALT AND MALT ROOTS

Preparative isolation of alcohol-soluble and water-soluble melanoidines from pale malt, caramel malt, coffee malt and malt roots was done. The distribution of melanoidines according to molecular weight and the spectral characterization of the separate fractions was studied by gel chromatography on Sephadex G-50. The melanoidines isolated from coffee malt have the largest molecular weights and those from pale malt the smallest. The alcohol-soluble melanoidines of malt are characterized by a greater diversity in spectra and absorbance maxima from 240 to 285 nm. The water-soluble melanoidines absorb in the region 265 to 283 nm.