The effect of irradiation and thermal process on beef heme iron concentration and color properties

The aim of this study was to evaluate the influence of irradiation and thermal process on the heme iron (heme-Fe) concentration and color properties of Brazilian cattle beef. Beef samples (patties and steaks) were irradiated at 0-10 kGy and cooked in a combination oven at 250 ºC for 9 minutes with 70% humidity. Total iron and heme iron (heme-Fe) concentrations were determined. The data were compared by multiple comparisons and fixed- effects ANOVA. Irradiation at doses higher than 5 kGy significantly altered the heme-Fe concentration. However, the sample preparation conditions interfered more in the heme-Fe content than did the irradiation. Depending on the animal species, meat heme iron levels between 35 and 52% of the total iron are used for dietetic calculations. In this study the percentage of heme-iron was, on average, 70% of the total iron showing that humidity is an important factor for its preservation. The samples were analyzed instrumentally for CIE L*, a*, and b* values.

Lactobacillus plantarum strains isolated from naturally fermented sausages and their technological properties for application as starter cultures

In the present study, technological properties of L. plantarum strains isolated from naturally fermented sausages manufactured in the South region of Brazil were investigated in order to obtain a starter culture. The technological properties evaluated were the following: ability to growth at different pH values, at different temperatures, in different salt concentrations and in the presence of commercial curing salt, fast production of acid, determination of D - and L - lactic acid; nitrate reductase activity; antagonistic activity and stability of the isolated cultures after fermentation, concentration, and freeze-drying process. The isolated strains showed effectiveness to improve technological properties as starter cultures.

The role of organic solvent amount in the lipase-catalyzed biodiesel production

This research note addresses the role of organic solvent amount in the production of fatty acid ethyl esters from soybean oil. N-hexane was chosen as solvent and two commercial immobilized lipases as catalysts, Novozym 435 and Lipozyme IM. The reactions were conducted in 6 hours, varying the solvent to oil ratio from zero to 50 (v/wt) and adopting adopting for Novozym 435: 65 ºC, enzyme concentration (E, wt%) = 5, oil to ethanol molar ratio (R) = 1:10, water addition (H, wt%) = 0, and for Lipozyme IM: 35 ºC, E = 5 wt%, R = 1:3, H = 10 wt%. For Lipozyme IM, an increase in solvent amount is shown to lead to an enhancement of reaction conversion, while a negligible effect was found for Novozym 435. When using 30 mL of solvent the reaction conversions were 88% for Lipozyme IM and 15% for Novozym 435.

Clarification of pineapple juice by microfiltration

In the present work, pineapple juice was first hydrolyzed with a commercial pectinase (Ultrazym 100 G) and then clarified by microfiltration. A tubular polyethersulfone membrane with an average cut-off of 0.3 µm and a total effective filtration area of 0.05 m² was applied. The transmembrane pressures were 1.5 and 3.0 bar, respectively, and the processes was conducted at room temperature. The results showed that the pineapple juice permeate fluxes were of 57.77 L/m²/hours (1.5 bar) and 46.85 L/m²/hours (3.0 bar). Concentration polarization and possibly fouling occurred during the processes. The best clarified juice fluxes were obtained when low transmembrane pressures (1.5 bar) were applied.

Effect of soaking and cooking on phytate concentration, minerals, and texture of food-type soybeans

The increasing consumption of soybeans due to its bioactive compounds has attracted interest in describing the grain's constituents and variation during processing. Phytate has been the aim of much research since it chelates essential minerals but also has beneficial antioxidant effects. This study evaluated the variation of phytate, calcium, zinc, and iron during soaking and cooking of soybeans. The phytate: Zn and phytate: Fe molar ratios were determined in order to estimate the bioavailability of these minerals. Six food-type varieties were used: BR 36, BRS 213, BRS 216, BRS 232, BRS 155, and Embrapa 48. The samples were soaked in water 3:1 (w/w) for 12 hours at room temperature and cooked. Cooking time was determined by modeling the softening of each variety using fractional conversion. Water content, phytate, and minerals were determined in raw, soaked and cooked samples. The water content of raw grains for all varieties was 9.9 g.100 g-1 increasing to a range of 58.1-63.7 g.100 g-1 after soaking and 63.1-66.0 g.100 g-1 after cooking. Soaking caused a significant reduction in phytate (23-30%), but cooking caused no additional reduction. The phytate: Zn molar ratio was 20 indicating that zinc absorption could be impaired, while the phytate: Fe molar ratio was 8, below the level of compromising absorption

Changes in guava (Psidium guajava L. var. Paluma) nectar volatile compounds concentration due to thermal processing and storage

Guava nectars were formulated for approximately 10, 12, or 14 ºBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 ºC/42 seconds) in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 ºC) or refrigerated (5 ± 2 ºC) under fluorescent light exposure and analyzed on the day after processing (time zero) and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC) -Mass Spectrometry (MS): hexanal, (E)-hex-2-enal, 1-hexenol, (Z)-hex-3-enol, (Z)-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001) in hexanal and (Z)-hex-3-enyl acetate (p = 0.0029). As for the storage time, there was a much greater decrease in the esters contents, such as (Z)-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

Flavonoids, total phenolics and antioxidant capacity: comparison between commercial green tea preparations

The potential health benefits attributed to green tea and its catechins such as antioxidant effects, cancer chemoprevention, and weight loss have led to a huge increase of green tea products in the food market. The objectives of this work were to analyze and compare these products in terms of phenolic contents and in vitro antioxidant capacity including tea bags, dehydrated leaves, and ready-to-drink preparations after standardization of the infusion preparation procedure. Total phenolics content in 1 cup of the different teas varied from 90 to 341 mg of catechin equivalents, and the highest and the lowest values were both those of the ready-to-drink products. Infusions prepared from tea bags had contents varying from 96 to 201 mg.200 mL-1, and there were no significant differences among batches. The DPPH radical scavenging and the Oxygen Radical Absorbing Capacities (ORAC) varied largely among the different tea preparations, from 23 to 131 mmoles of Trolox Equivalents (TE).200 mL-1 (DPPH), and from 1.2 to 5.1 mmoles of TE.200 mL-1 (ORAC), but again there were no differences among infusions or ready-to-drink commercial preparations. However, the antioxidant capacity of ready-to-drink products was partially due to the presence of other non-phenolic compounds such as ascorbic acid

Conjugated linoleic acid supplementation: lipid content and hepatic histology in healthy Wistar rats

This work aimed to evaluate the effects of the consumption of two commercial conjugated linoleic acid (CLA) mixtures on lipid content and liver histology of healthy rats. The investigation was carried out using thirty rats divided into three groups: C (control), AE (AdvantEdge®CLA), and CO (CLA One®). The concentration of CLA was 2% of feed consumption, and the animals were supplemented daily for 42 days. The total lipid content of the liver was determined, and the histology of the organ was examined by Transmission Electronic Microscopy. The results of total liver lipid contents did not exhibit significant differences between the groups. With regard to hepatic histology, it was observed that although fat globules were visibly present in higher numbers and bigger size in the CLA groups, the organ histology was considered normal since both cytoplasm and organelles showed integrity. It was concluded that even though liver microscopic images indicated the presence of fat globules in the liver, from a statistical point of view, the supplementation for 42 days did not bring about lipid accumulation, nor did it alter hepatic histology.

Determination of pectin methylesterase activity in commercial pectinases and study of the inactivation kinetics through two potentiometric procedures

Pectinases are enzymes that degrade pectic substances and are widely used in juice and fruit beverages to improve the quality of the process. The objective of this study was to determine the optimum pH and temperature of two samples of commercial pectinases and propose an alternative procedure to determine the residual activity comparing the data with those of the traditional procedure. The pectin methylesterase (PME) activity in Pectinex 100 L Plus and Panzyn Clears was determined by potentiometry. The reaction consisted of 5.00 mg.mL-1 apple pectin, 0.100 mol.L-1 NaCl, and 50 µL enzyme to a total volume of 30 mL. The pectin reaction in the presence of PME in all experiments revealed a first order kinetics. The PME in the two enzyme preparations showed higher activity at pH 4.0 to 4.5 and temperature of 45 ºC. From the results of both procedures ΔV NaOH/Δt and ΔpH/Δt, it was concluded that the inactivation of PME occurred at 75 ºC. The results obtained from the ratio ΔpH/Δt showed good correlation with those obtained from the ratio ΔV NaOH/Δt. In the reaction accompanied by the ratio ΔpH/Δt, the release of H3O+ occurred in the real time reaction.

Effect of pectinolitic enzymes on the physical properties of caja-manga (Spondias cytherea Sonn.) pulp

Cajá-manga, also known as golden apple and hog-plum, is an exotic fruit native from Îles de la Société (French Polynesia), which was first introduced in Brazil in 1985. The pulp of ripe fruit was treated with the commercial enzymatic pool and its effect was evaluated in terms of yield, as well as the physical properties viscosity, turbidity and color (L* values). Response surface methodology was used and three levels were adopted for the independent variables temperature (30, 40, and 50 ºC), incubation time (30, 60 and 90 minutes) and enzyme concentration (0.01, 0.05, 0.09 v/v%). A central composite statistical design was used to guide the experimental work. The enzyme treatment highly increased both juice yield (up to 56%) and color (up to 8.6%) and strongly decreased viscosity (up to 57.4%), clarity (up to 77%) and turbidity (up to 85.5%). Incubation time was the most interacting facto, whereas temperature was the least one. Optimization analysis was carried out to reduce enzyme concentration to a minimum by superposing the contour plots of the tested properties, and the recommended ranges of the variables enzyme concentration, process temperature and incubation time were, respectively, 0.042-0.068%, 47.0-49.0 ºC and 82-90 minutes.

Commercial spices and industrial ingredients: evaluation of antioxidant capacity and flavonoids content for functional foods development

The aim of this work was to evaluate spices and industrial ingredients for the development of functional foods with high phenolic contents and antioxidant capacity. Basil, bay, chives, onion, oregano, parsley, rosemary, turmeric and powdered industrial ingredients (β-carotene, green tea extract, lutein, lycopene and olive extract) had their in vitro antioxidant capacity evaluated by means of the Folin-Ciocalteu reducing capacity and DPPH scavenging ability. Flavonoids identification and quantification were performed by High Performance Liquid Chromatography (HPLC). The results showed that spices presented a large variation in flavonoids content and in vitro antioxidant capacity, according to kind, brand and batches. Oregano had the highest antioxidant capacity and parsley had the highest flavonoid content. The industrial ingredient with the highest antioxidant capacity was green tea extract, which presented a high content of epigalocatechin gallate. Olive extract also showed a high antioxidant activity and it was a good source of chlorogenic acid. This study suggests that oregano, parsley, olive and green tea extract have an excellent potential for the development of functional foods rich in flavonoids as antioxidant, as long as the variability between batches/brands is controlled.

Simultaneous α-amylase and protease production by the soil bacterium Bacillus sp. SMIA-2 under submerged culture using whey protein concentrate and corn steep liquor: compatibility of enzymes with commercial detergents

Protease and α-amylase production by a thermophilic Bacillus sp. SMIA-2 cultivated in liquid cultures containing 0.25% (w/v) starch as a carbon source reached a maximum at 18 hours (47 U.mg-1 Protein) and 36 hours (325 U.mg-1 Protein), respectively. Culture medium supplementation with whey protein concentrate (0.1%, w/v) and corn steep liquor (0.3%, w/v) not only improved the production of both enzymes but also enabled them to be produced simultaneously. Under these conditions, α-amylase and protease production reached a maximum in 18 hours with levels of 401 U.mg-1 protein and 78 U.mg-1 protein, respectively. The compatibility of the enzymes produced with commercial laundry detergent was investigated. In the presence of Campeiro® detergent, α-amylase activity increased while protease activity decreased by about 27%. These enzymes improved the cleaning power of Campeiro® detergent since they were able to remove egg yolk and tomato sauce stains when used in this detergent.

Viscosity of egg white from hens of different strains fed with commercial and natural additives

Yolk color and egg white (albumen) cleanliness and viscosity are important parameters by which consumers judge the quality of eggs. This study aimed to investigate changes in albumen viscosity during storage of eggs for up to 36 days from two different commercial laying hen strains (Carijo Barbada and Isa Brown) fed a diet containing annatto (1.5 and 2.0%) or a synthetic additive without synthetic colorants (control). Analyses of humidity, albumen height, pH, viscosity, foam formation, and stability were carried out on eggs. Carijo Barbada strain had smaller albumen, lower humidity and higher egg white viscosity than Isa Brown strain; however, with storage, viscosity lowered significantly on both strains. Initially, the addition of 2.0% of annatto or a synthetic additive increased viscosity in both strains, but with storage only the control maintained longer viscosity. Lower viscosity did not change foam density and stability.

Analytical characteristics and discrimination of Brazilian commercial grape juice, nectar, and beverage

The production and commercialization of Brazilian grape juice is increasing annually, mainly due to its typicality, quality, and nutritional value. The present research was carried out in view of the great significance of Brazilian grape juice for the grape and wine industry. The purpose of this study, therefore, was to assess its composition as well as the discrimination between grape juice and other beverages. Twenty four samples of whole, sweetened, and reprocessed grape juices, grape nectar, and grape beverage were evaluated. Classical variables were analyzed by means of physicochemical methods; tartaric and malic acids, by HPLC; methanol, by gas chromatography; minerals, by atomic absorption spectrophotometry. These products were discriminated by the Principal Component Analysis (PCA). Results show that whole and sweetened grape juices were discriminated from other grape products because they featured higher values of total soluble solids, tartaric and malic acids, most minerals, phenolic compounds, and K/Na ratio, whereas grape nectar and grape beverage presented higher values of ºBrix/titratable acidity ratio. Reprocessed juice was discriminated due to its higher concentrations of Li and Na and lower hue.