Flavia Maria Netto

Effect of Encapsulating Materials on Water Sorption, Glass Transition and Stability of Juice From Immature Acerola

Immature acerola juice was dehydrated by spray drying, using as encapsulating material maltodextrin DE25, arabic gum, or a mixture of both in different proportions. A constant ratio of 1:1 was kept between juice solids and encapsulating material. The effect of encapsulation materials on water sorption, glass transition, and physical properties of encapsulated immature acerola juice was investigated. The monolayer moisture of the encapsulated juices, calculated according to the GAB theory, varied from 5.11 to 5.73g H2O/100g of solids (25°C). The glass transition temperature (Tg) of maltodextrin and gum arabic varied from 60 (aw 0.33) to 38°C (aw 0.54), and from 62 (aw 0.33) to 42.6°C (aw 0.54), respectively. The addition of juice to the encapsulating materials decreased the Tg of the juice powder to 39.5–41.3°C (aw 0.33) and 1.84–8.05°C (aw 0.54), but no marked differences were found among the juice powders. The critical aw, i.e., the point of onset of physical alterations in the encapsulated materials, was higher than the corresponding monolayer values. Stickiness was observed at temperatures close to Tg, and collapse occurred at temperatures of 20°C or more above the Tg. Maltodextrin DE25 and gum arabic offered equivalent contributions to the stability of the system.Immature acerola juice was dehydrated by spray drying, using as encapsulating material maltodextrin DE25, arabic gum, or a mixture of both in different proportions. A constant ratio of 1:1 was kept between juice solids and encapsulating material. The effect of encapsulation materials on water sorption, glass transition, and physical properties of encapsulated immature acerola juice was investigated. The monolayer moisture of the encapsulated juices, calculated according to the GAB theory, varied from 5.11 to 5.73g H2O/100g of solids (25°C). The glass transition temperature (Tg) of maltodextrin and gum arabic varied from 60 (aw 0.33) to 38°C (aw 0.54), and from 62 (aw 0.33) to 42.6°C (aw 0.54), respectively. The addition of juice to the encapsulating materials decreased the Tg of the juice powder to 39.5–41.3°C (aw 0.33) and 1.84–8.05°C (aw 0.54), but no marked differences were found among the juice powders. The critical aw, i.e., the point of onset of physical alterations in the encapsulated materials, wa...

Preservation of β-Carotene from Carrots

Beta-carotene acts as a pro-vitamin A or anti-cancer compound. Carrots contain the highest amount of beta-carotene of common fruits and vegetables, but each year 25% of carrot production is lost in the U.S. during processing and storage, while, at the same time, the market demand increases. This article is a review of the most recent studies concerning beta-carotene retention in carrots during processing and storage. Reducing the water activity by adding some aw lowering ingredients results in poor shelf-life. Drying or freezing gives better retention during storage than reducing the water activity, if the process is well controlled. Canning or freeze-drying were shown to be more effective. The trans form of beta-carotene in carrots is replaced by the cis form during processing. Beta-Carotene can be extracted from carrots, but the half-life of free beta-carotene is reduced to 2 d in the juice extract at room temperature. By encapsulation methods,the half-life can be increased by 6 months.

Microcapsules of a Casein Hydrolysate: Production, Characterization, and Application in Protein Bars

The aim of this work was to encapsulate a casein hydrolysate by spray drying using maltodextrins (DE 10 and 20) as wall materials and to evaluate the efficiency of the microencapsulation in attenuating the bitter taste of the hydrolysate using protein bars as the model system. Microcapsules were evaluated for morphology (SEM), particle size, hygroscopicity, solubility, thermal behavior (DSC), and bitter taste with a trained sensory panel by a paired comparison test (nonencapsulated samples vs. encapsulated samples). Bars were prepared with the addition of 3% casein hydrolysate at free or both encapsulated forms, and were then evaluated for their moisture, water activity (aw) and for their bitter taste by a ranking test. Microcapsules were of the matrix type, having continuous surfaces with no apparent porosity for both coatings. Both encapsulated casein hydrolysates had similar hygroscopicity, and lower values than free encapsulated hydrolysates. The degree of hydrolysis of the maltodextrin influenced only the particle size and Tg. The sensory panel considered the protein bars produced with both encapsulated materials less bitter (p < 0.05) than those produced with the free casein hydrolysates. Microencapsulation by spray drying with maltodextrin DE 10 and 20 was successful to attenuate the bitter taste and the hygroscopicity of casein hydrolysates.

Effect of water content on the glass transition, caking and stickiness of protein hydrolysates

Abstract Protein hydrolysates play an important function in many special dietary foods, e.g. for infants, those with genetic disorders, athletes and geriatrics. Because of hydrolysis these materials are more hygroscopic than the initial intact protein. In this reset the moisture sorption isotherms and the glass transition profile as a function of moisture content for fish protein hydrolysates (FPH), whey protein hydrolysates (WPH) and casein hydrolysates (CH) were determined. The properties of each hydrolysates were related to molecular weight with a lower glass transition curve at lower molecular weight, the Tg was proportional to degree of hydrolysis. These hydrolysates may be as important as sugars in lowering Tg. Fish moisture sorption was related to hydrolysis. CH was less susceptible to caking than FPH and WPH.

Surfactant systems for nasal zidovudine delivery: structural, rheological and mucoadhesive properties

Objectives Zidovudine is the antiretroviral drug most frequently used for the treatment of AIDS. Although its effectiveness is recognized, it undergoes extensive first‐pass metabolism and exhibits poor oral bioavailability. The nasal route is an option for enhanced therapeutic efficacy and to reduce the extent of the first‐pass effect. There are some mechanisms that limit intranasal absorption, such as mucociliary clearance, which rapidly removes the formulation from the nasal cavity. To improve the nasal residence time of zidovudine on the nasal mucosa, we aimed to develop a mucoadhesive surfactant system for zidovudine nasal administration.

Characterization and ACE‐Inhibitory Activity of Amaranth Proteins

Amaranth seeds have been considered as an excellent alternative or complementary source of food protein due to their balanced amino acid composition. However, their potential as a source of bioactive peptides has not been explored. The present study is aimed at characterizing and evaluating the activity of the angiotensin converting enzyme inhibitor of the amaranth protein concentrate and of hydrolysates produced with Alcalase. The protein concentrate, after simulated gastrointestinal digestion, showed lower angiotensin converting enzyme-inhibitory activity (IC(50) of 0.439 +/- 0.018 mg protein/mL and 0.475 +/- 0.021 mg protein/mL, for untreated and heat treated protein concentrate, respectively) than the hydrolysates produced with Alcalase, before and after simulated gastrointestinal digestion (IC(50) 0.118 +/- 0.009, 0.123 +/- 0.007, 0.137 +/- 0.002, and 0.176 +/- 0.014 mg protein/mL, respectively). The simulated gastrointestinal digestion (pepsin-pancreatin) did not significantly alter the angiotensin-converting enzyme inhibiting activity of the Alcalase hydrolysates, suggesting that the peptides of the hydrolysates were resistant to gastrointestinal hydrolysis. These results highlight the angiotensin converting enzyme-inhibitory potential of amaranth proteins, which is an indication of their health-promoting potential.

Chemical Composition and Antioxidant Activity of Juices from Mature and Immature Acerola (Malpighia emarginata DC)

Chemical composition and antioxidant activity of juice from immature and mature acerola and of concentrated juice from immature acerola were determined. Tartaric, malic and citric acids and a high content of ascorbic acid were found in all the juices. Vitamin C contents were 4.80, 1.90 and 0.97 g/100 g for the concentrated immature, the immature, and the mature acerola juices respectively. The total phenol contents decreased during ripening, from 3.8 mg of catechin/g for immature acerola juice to 1.4 mg of catechin/g for mature acerola juice. The concentrated immature juice had a content of 9.2mg of catechin/g of juice. Catechin, gallic acid, coumaric acid, syringic acid, caffeic acid and ferrulic acid were detected in immature acerola juice by HPLC analysis whereas mature acerola juice showed only one predominant peak with a retention time similar to that of ferrulic acid. The concentrated juice from immature acerola reduced the oxidation of methyl linoleate by 57.2% while the juice from immature acerola reduced the oxidation by 28.1%. These results stated that the antioxidant potential of the acerola juice depended on its content of phenolic compounds and the vitamin C.

Effect of spray drying on the sensory and physical properties of hydrolysed casein using gum arabic as the carrier

This study was aimed at spray drying hydrolysed casein using gum Arabic as the carrier agent, in order to decrease the bitter taste. Three formulations with differing proportions of hydrolysed casein: gum Arabic (10:90, 20:80 and 30:70) were prepared and characterized. They were evaluated for their moisture content, water activity, hygroscopicity, dispersibility in water and in oil, particle size and distribution, particle morphology, thermal behaviour (DSC) and bitter taste by a trained sensory panel using a paired-comparison test (free samples vs. spray dried samples). The proportion of hydrolysed casein did not affect the morphology of the microspheres. The spray drying process increased product stability and modified the dissolution time, but had no effect on the ability of the material to dissolve in either water or oil. The sensory tests showed that the spray drying process using gum Arabic as the carrier was efficient in attenuating or masking the bitter taste of the hydrolysed casein.

Elaboration of sausage using minced fish of Nile tilapia filleting waste

ABSTRACT The objective of this study was to evaluate the inclusion of minced fish (MF) (0, 20, 40, 60, 80 and 100%), obtained from Nile tilapia filleting waste, in sausage and determine their physicochemical, nutritional and sensory properties. The sausages showed a decrease in protein and increase in fat content with increasing inclusion of MF. The nutritional quality of the products was high, with digestibility over 85%. The parameters of texture instrumental and yellow color (b*) decreased with the increasing inclusion of MF. The sensory evaluation of the color showed that the maximum level of inclusion of MF was not well accepted by the panelists. The sausage with the best acceptance for the flavor attribute was those with 60% of MF. The results showed good nutritional quality of sausages utilizing MF of Nile tilapia filleting waste and according to the sensory evaluation, the maximum level of inclusion should not exceed 60%. Key words: Oreochromis niloticus , sausage, nutritional quality, minced fish, sensory acceptance, texture

Evaluation of the Hypotensive Potential of Bovine and Porcine Collagen Hydrolysates

Angiotensin-converting enzyme (ACE) inhibitory activity and antihypertensive activity of bovine and porcine collagen hydrolysates in spontaneously hypertensive rats (SHR) were investigated. The hydrolyzed collagens were subjected to ultrafiltration using membranes with cutoffs of 30-50 kDa (permeate P1), 5-8 kDa (permeate P2), or 1-2 kDa (permeate P3) in order to obtain products with a narrower range of molecular size. The hydrolyzed bovine and porcine collagens and their permeates showed low ACE inhibitory activity (50% inhibitory concentration [IC(50)] = 5.42-15.58 mg of protein/mL). However, after in vitro gastrointestinal digestion, a significant increase in the ACE inhibitory potency of the hydrolyzed collagens was observed (IC(50) = 0.97-4.02 mg of protein/mL). Permeates had a higher ACE inhibitory activity and hypotensive activity than non-ultrafiltered hydrolysates. The P1 permeate of bovine and porcine collagen and the P3 fraction of the porcine collagen hydrolysate exhibited the best antihypertensive activity in vivo, promoting a maximum reduction in blood pressure of 22 mm Hg, 21.33 mm Hg, and 21.33 mm Hg, respectively, while lisinopril promoted a maximum reduction of 51.00 mm Hg. These results suggest that the commercial collagen hydrolysates of bovine and porcine origin may be a potential source of bioactive peptides.