Use of ultrafiltration for preparing improved tomato pulp

The characteristics of high-quality tomato pulp (commercial def.: crushed or diced tomatoes with about 30% tomato juice as packing medium) canned with tomato juice pulp enriched by ultrafiltration as packing medium were compared with those covered with conventional vacuum-concentrated juice.
Both hot- and cold-break products were prepared and those containing 20% serum-reduced packing juice proved to be the best, showing no signs of syneresis on storage and with improvements in sensory properties, colour and non-enzymatic browning; some volatile components were reduced.     

ANTENNAL AND BEHAVIORAL RESPONSES OF GRAPEVINE MOTH <Emphasis Type="Italic">Lobesia botrana</Emphasis> FEMALES TO VOLATILES FROM GRAPEVINE

Grapevine moth Lobesia botrana is the economically most important insect of grapevine Vitis vinifera in Europe. Flower buds, flowers, and green berries of Chardonnay grapevine are known to attract L. botrana for oviposition. The volatile compounds collected from these phenological stages were studied by gas chromatography—mass spectrometry, and the antennal response of L. botrana females to these headspace collections was recorded by gas chromatography—electroantennography. The compounds found in all phenological stages, which consistently elicited a strong antennal response, were pentadecane, nonanal, and -farnesene. In a wind tunnel, gravid L. botrana females flew upwind to green grapes, as well as to headspace collections from these berries released by a piezoelectric sprayer release device. However, no females landed at the source of headspace volatiles, possibly due to inappropriate concentrations or biased ratios of compounds in the headspace extracts.     

Kinetic Study on Color Changes in Milk Due to Heat

Analysis of changes in terms of color difference (ΔE) and yellowness index (YI) permits evaluation of severity of heat treatment of milk. Both ΔE and YI increased at constant temperature following zero-order kinetics, at temperatures between 90 and 130°C for 1 to 60 min. Activation energy, according to the Arrhenius equation, was 101.8 and 117.5 KJ/mol for ΔE and YI, respectively. Comparison of instrumental and sensory data showed a minimum ΔE of 3.8 would be attained before visual perception of milk browning. Color values, such as ΔE or YI, are proposed as the simplest and most reproducible indices of commercial milk quality.     

Solute Effects at High Water Activity on Nonenzymatic Browning of Glucose-Lysine Solutions

The effect of different polyols (glycerol, propylene glycol, sorbitol, 1,3-butylene glycol, polyethylene glycol200, and polyethylene glycol 400) and various alkali metal chlorides (KCl, NaCl, LiCl, and CsCl) on the kinetics of nonenzymatic browning in glucose-lysine solutions, of high water activity (a_w) was studied. No particular inhibitory or promoting effect on browning of glucose-lysine solutions, when adjusting a, with the various polyols, was found. The alkali metal chlorides had a significant influence on the rate of browning and the relative effect of cations (Li > Na > K, Cs) paralleled the hydrated ionicradii in solutions.     

THE EXACT PENETRATION MODEL OF DIFFUSION IN MULTICOMPONENT IDEAL GAS MIXTURES. ANALYTICAL AND NUMERICAL SOLUTIONS

An exact analytical solution is derived for the penetration model of diffusion in multicomponent ideal gas mixtures at constant pressure and temperature. It takes the form of a matrizant solution to the continuity and Maxwell-Stefan equations transformed by introduction of a similarity variable, and includes as special cases the corresponding binary and linearized theory solutions

Direct numerical implementation of the analytical solution is computationally inefficient, but an alternative finite-difference algorithm is developed in which the transformed equations are solved by Euler's method with a simple shooting technique. Sample calculations are reported for two ternary diffusion problems

It is concluded on the basis of the theoretical and numerical results that the linearized theory predictions should provide an excellent approximation to the exact solution of the penetration model.     

SUPERCRITICAL CARBON DIOXIDE SELECTIVITY TO FRACTIONATE PHENOLIC COMPOUNDS FROM THE DRY ETHANOLIC EXTRACT OF PROPOLIS

The global yield and composition of extracts obtained by supercritical carbon dioxide (SC-CO₂) extraction from a dry ethanolic extract of propolis were measured in order to determine the possibility of using SC-CO₂ to fractionate components of interest present in these extracts. The global yield extraction was measured, and also the concentrations of the following phenolic compounds in the resulting supercritical fluid extracts (SFEs): 3,5-diprenyl-4-hydroxycinnamic acid (known as artepillin C), 3-prenyl-4-hydroxycinnamic acid, 4-hydroxycinnamic acid ( p- coumaric acid) and 4-methoxy-3,5,7-trihydroxyflavone (kaempferide), of which artepillin C was the target component of greatest interest. The results showed extraction yields between 3.82 (at 150 bar) and 13.07% (at 350 bar), which could be highly correlated with the density of the SC-CO₂ at a constant temperature of 60C. The resulting concentrations in the SFE indicated that the selectivity of the carbon dioxide could be manipulated, and it was more selective at lower pressures, although with lower extraction yields.

PRACTICAL APPLICATIONS

Supercritical fluid extraction is an interesting process for the production of natural extracts because it is a clean process, and extractions using carbon dioxide (CO₂) as the solvent have been gaining attention in recent years. This study presented important aspects with respect to the fractionation of a dry ethanolic extract of propolis using supercritical carbon dioxide, and it is important to explore the potential applications of propolis extracts and the biological properties of its fractions in the food, pharmaceutical and cosmetic industries, such as in dental hygiene products, wound healing creams and antibacterial soaps.     

Source Allocation of Aliphatic and Polycyclic Aromatic Hydrocarbons in Particulate-Phase (PM10) in the City of Valdivia,Chile

The concentration and signature of n-alkanes (n-C₁₀ to n-C₃₃) and 18 PAHs were determined in air filters across a year period (2010) in an urban area of the city of Valdivia, Chile. Filter samples were extracted using sohxlet apparatus and analyzed by GC-MS techniques. Concentrations of total hydrocarbons ranged from 45–352 ng.m^?3 and total PAHs ranged from 2.93–78.01 ng.m^?3. Concentrations of hydrocarbons during the summer were high (288–352 ng.m^-3) and reduced when the autumn began (45–79 ng.m^?3) to then increase almost linearly to the next summer. The drop in concentration was attributed in part to the significant reduction of traffic when summer ends as tourists leave the city (about 9–15% of the total cars circulating). Results from the chemometric technique of Polytopic Vector Analysis (PVA) indicated three main sources for the alkanes: biogenic (terrestrial plants), signatures of oil combustion, and an unconfirmed source which is thought to come from non specific organic matter degradation. Total PAHs correlated well with total particulate matter with a R² = 0.94. Levels of PAHs in the atmosphere were higher during the winter (6.85–78.01 ng.m^?3) period than the rest of the year (2.93–36.30 ng.m^?3). PVA results indicate three key sources of PAHs and two of those sources derived from oil combustion and biomass burning.     

SENSORY QUALITY PERFORMANCE OF TWO NECTARINE FLESH TYPOLOGIES EXPOSED TO DISTANT MARKET CONDITIONS

The objective of this research was to evaluate the shelf life of two nectarine flesh typologies in order to determine the exporting potential of fresh nectarines to distant markets. "Maria Dolce" (subacid fruit type) and "Venus" (normal fruit type) nectarines were harvested at two maturity stages, based on fruit ground color. Fruits were stored at 0C and 90% R.H. for 14 or 42 days, simulating storage duration aimed respectively to shipping to close or distant marketplaces. Nectarines were evaluated after a period of ripening at 20C, when flesh firmness reached 9.8–19.6 N. Visual appearance, color, aroma, flesh texture, sweetness, sourness, juiciness, flavor and acceptability were evaluated. Both varieties presented a better eating quality when harvest was delayed. "Maria Dolce" presented high storage ability, reaching even at 42 days the same acceptability of fruit not subjected to cold storage. "Venus" showed a significant decrease in acceptability, indicating a not sufficient tolerance to long storage.

PRACTICAL APPLICATIONS

The poor eating quality of fresh nectarines destined to distant markets is one of the main problems that are facing some countries as Chile, which is a conspicuous exporter of off-season stone fruits to the Northern Hemisphere and Latin America. This research is focused on the comparison of quality of a normal fruit type nectarine, which is one of the most cultivated in Chile, and of a subacid nectarine; experimental design simulated two exportation regimes for close or distant marketplaces. Subacid types have been recently available in the world variety assortment system and the sensorial quality performance has yet not been tested after long postharvest storage.     

Relationship Between Blocked Lysine and Carbohydrate Composition of Infant Formulas

The quantity of blocked lysine in spray-dried infant formulas in Italy was calculated by the furosine method. This quantity was then correlated with the composition of the carbohydrate fraction. In formulas containing only lactose as carbohydrate its presence in large quantities (6.7–7.5 g/100 mL of formula as fed), with a lysine-rich protein fraction, may lead to amino acid blocking of >20%. In formulas in which lactose was substituted with low-DE maltodextrin a reduction of lysine blocking was possible. Addition of glucose may result in high levels of blocked lysine.