Luis Alberto Brumovsky

Quantification of Resistant Starch in Several Starch Sources Treated Thermally

The purpose of the research was to determine the effect of heat-moisture treatment at different phases and temperatures on resistance starch (RS) level on native starches samples of several botanical sources and to evaluate the thermal stability of different granules. Samples of potato, cassava, wheat, and corn starches were moisturized up to 30% wet basis and then treated in a convection oven at 80, 100, and 120°C during 40 and 60 minutes. RS was determined gravimetrically by a modification of Method 991.43 of the AOAC for the determination of total dietary fibre. All samples were submitted to different thermal analysis in a range from 40 to 180°C at 10°C/min. Overall, in the treated samples an increase of RS was observed, being the corn starch sample treated at 120°C and 60 minutes – the one that presented the highest content of RS (4.2%). Other treated samples showed a decrease in the gelatinization enthalpies with the presence of granular fusion, indicating internal re-arrangement, an increase in the gelatinization temperature and the thermo stability below 95°C.

Influence of Drying Temperature on the Physical and Microbiological Parameters and the Quality of Dried Green Onion

The aim of this research was to determine the influence of drying temperature on the physical and microbiological parameters of the green onion and to evaluate the quality and shelf stability of the dried product. To evaluate the stability during storage, measurements of water activity, color parameters, and microbial survival were taken. Drying temperature had little influence on the adsorption isotherms and rehydration rates but had a strong influence on the color parameters and microbial survival. All stability parameters were improved at drying temperature of 70°C. Changes in color limit the shelf life of this product to about 30 days.

Microbiological and physicochemical analysis of yateí (Tetragonisca angustula) honey for assessing quality standards and commercialization.

Due to the interest in the production and trading of yateí (Tetragonisca angustula) honey in the province of Misiones, Argentina, in this work we assessed microbiological and physicochemical parameters in order to contribute to the elaboration of standards for quality control and promote commercialization. Results showed that yateí honey samples had significantly different microbiological and physicochemical characteristics in comparison to established quality standards for Apis mellifera honey. Thus, we observed that values for pH (3.72), glucose (19.01 g/100g) and fructose (23.74 g/100g) were lower than A. mellifera quality standards, while acidity (79.42 meq/kg), moisture (24%), and mould and yeast count (MY) (3.02 log CFU/g) were higher. The acid content was correlated with glucose (R2=0.75) and fructose (R2=0.68) content, and also with mould and yeast counts (R2=0.45) to a lesser extent. The incidence of microorganisms in yateí honey samples reached 42.85% and 39% for Clostridium sulfite-reducers and Bacillus spp., respectively. No C. botulinum or B. cereus cells were detected. Enterococcus spp. and Staphylococcus spp. incidence was similar (ca. 7.14%), whereas Escherichia coli and Salmonella spp. were not detected. We conclude that the microbiological and physicochemical properties of yateí honey are different from those of A. mellifera honey; hence, different quality standards could be implemented to promote its commercialization.

Effects of Spray Drying Conditions on the Stability and Antioxidant Properties of Spray-Dried Soluble Maté

Abstract The aim of this research was to evaluate the stability of spray-dried soluble maté (Ilex paraguariensis) and its total polyphenol content determined with the Folin–Ciocalteu assay, after it was elaborated with three different maltodextrin concentrations (0, 7.05 and 14.10% w/v) using experimental data of water activities and glass transition temperatures. Adsorption isotherms were determined for these three materials at 25°C between water activity values (aw) of 0.1 and 0.85 (resulting in values of water content between 0.04 and 0.33 g of water/g of dried solid). Glass transition temperatures varied from 15 to 52°C. At room temperature powder containing 14.10% of maltodextrin at aw=0.55 was below the glass transition temperature, while the two other compositions were below their Tg and stable at aw=0.40. In the spray drying conditions analyzed, the loss of polyphenolic compounds is negligible. The total polyphenol content varied between 28 and 45 chlorogenic acid equivalents (g % dry powder).

In vitro digestibility and pasting properties of epichlorohydrin modified cassava starch

Purpose The purpose of this study was to analyze the influence of epichlorohydrin (ECH) concentration and reaction time on the food-grade resistant starch production and its pasting properties by using native cassava starch of Misiones-Argentina origin. Design/methodology/approach Cassava starch was modified using ECH (0.30 and 0.15 per cent) during 4 or 8 h. Digestibility was evaluated by determining resistant starch as total dietary fiber. Pasting properties and the cross-linking degree were studied using a micro-viscoamylograph (Brabender). Findings Resistant starch content was not influenced by ECH concentration and reaction time. Cross-linking was detected at higher reaction times (8 h) and ECH concentrations (0.30 per cent), where a decrease in viscosity peaks by more than 80 per cent was observed. Both pasting temperature and breakdown were increased, whereas a decrease in retrogradation was detected. Practical implications Starches can be suitable for different food applications. This is because of the ability to modify its pasting properties and the invariability of the in vitro digestibility of cassava starch as a result of using ECH (at concentrations approved by local and regional legislation) and reaction times of 4 and 8 h. Originality/value Information related to the modification of cassava starch using ECH is scarce or not available nowadays in literature.

Bioavailability and antioxidant effect of the Ilex Paraguariensis polyphenols

Purpose – The purpose of this study was to evaluate in vivo the bioavailability of the Ilex paraguariensis polyphenols due to total polyphenols and changes in antioxidant capacity (AOC) in human plasma after an acute intake of 300 ml of an infusion of yerba mate (YM) for 120 minutes. Also, we evaluated the variation of plasma protein or plasma uric acid after the acute intake of YM infusion. Design/methodology/approach – Seventeen healthy young volunteers participated in the determining plasma of total polyphenols concentration (TPC, Folin-Ciocalteu method), plasma AOC for ferric reducing antioxidant power (FRAP) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid diammonium salt [ABTS] methods), plasmatic uric acid and plasma total protein over the 120 minutes test. Findings – It was found that the bioavailability of YM polyphenols during 120 minutes was 49.3 ± 11.9 per cent, the TPC was increased to 6.0 ± 1.5 per cent, the plasma AOC was increased by FRAP 8.3 ± 3.3 per cent and by ABTS 6.0 ± 2.0 pe...