Optimization and Characterization of Protein Extraction from Asparagus Leafy By-Products.

Asparagus production generates significant amounts of by-products during the summer and post-harvest growth period. By-products can be good sources of nutrients and phytochemicals. The interest in increasing the availability of proteins for human consumption has led to the use of new plant sources rich in proteins. The objective of this study was to use response surface methodology (RSM) to optimize the aqueous extraction process of proteins from asparagus leafy by-products, for the production of new protein ingredients. The optimum extraction condition was at pH 9, with 40 min of extraction at 50 °C, and the concentration was fixed at 5 g·L-1. The isolate obtained presented 90.48% protein with 43.47% protein yield. Amino acids such as alanine, proline, valine, leucine/isoleucine, asparagine, and phenylalanine were identified, and the antioxidant activity for 2,2 AZINO BIS (3-ethylbenzo thiazoline 6 sulfonic acid diammonium salt) was 145.76 equivalent to Trolox µmol.100g-1 and for DPPH 65.21 equivalent to Trolox µmol.100g-1. The product presented favorable technological properties (water absorption capacity 4.49 g·g-1 and oil absorption capacity 3.47 g·g-1) and the color tended towards dark green (L* 31.91, a* -1.01, b* -2.11). The protein isolate obtained through the extraction optimization process showed high potential to be used as a protein ingredient.

High Value-Added Products from Food Waste.

Knowledge and use of technologies can transform waste into sustainable solutions [...].

Acacia mearnsii gum: A residue as an alternative gum Arabic for food stabilizer.

Acacia mearnsii gum is not commercially exploited, being characterized as residue from A. mearnsii cultivation. This work investigated the A. mearnsii gum polysaccharide composition, its cytotoxicity and the technological effect as a stabilizer in ice cream. A. mearnsii gum showed a similar chemical structure to commercial gum Arabic and did not decrease the viability and proliferation of fibroblast cells (Balb/3T3) and hepatocarcinoma (HepG2). Rheological tests showed that the ice cream stabilized by the A. mearnsii gum had a more structured system (more interactions between the mixture components) and the same melting characteristics as the ice cream samples made with commercial gum Arabic. The results showed that A. mearnsii gum, which is actually an agro-industrial residue from tannin production for industry, is a potential stabilizing gum for the food industry, contributing to the economic development of the exploitation chain of A. mearnsii products and by-products.

Use of asparagus flour from non-commercial plants (residue) for functional pasta production: Asparagus flour for functional pasta production.

The objective this study was enrich a pasta with non-commercial asparagus flour (AF). Six treatments were prepared: control (without AF), with 5, 10, 15, 20 and 25% of AF. Analyzes of antioxidants and bioactive compounds of AF and pasta, and the quality of pasta (color, optimal cooking time, water absorption capacity, cooking loss, texture and centesimal composition) were evaluated. The higher content of polyphenols and flavonoids were found in P25, as well as higher antioxidant activity. The addition of AF influenced the pasta color, decreasing the L* and a*, and increasing b* (p < 0.05). T he cooking time, water absorption, cohesiveness and springiness decreased with an increasing of AF (p < 0.05). The cooking loss, firmness, hardness and protein content increased with AF addition (p < 0.05). Thus, AF can be used to give an adequate destination to asparagus residue and has a potential application for the enrichment with protein and bioactive compounds of pasta.

Reduction in lignin content and increase in the antioxidant capacity of corn and sugarcane silages treated with an enzymatic complex produced by white rot fungus.

The objective was to evaluate the effect of the addition of 0, 10, 20, and 30 mg.kg-1 of natural matter of a lignocellulosic enzymatic complex produced by the white rot fungus on the chemical composition, cumulative gas production in vitro, and antioxidant compounds of corn and sugarcane silages. After being chopped and treated with the enzymatic complex, the plants were packed in vacuum-sealed bags. After 60 days, the mini silos were opened and the samples were dried in a forced ventilation oven at 55 °C for analysis of the proposed parameters. The experiment was conducted in a completely randomized design with four replicates per treatment. In the corn silage, there was a linear reduction in the lignin concentration. In the sugarcane silage showed a reduction of 12% in the lignin concentration, a linear reduction in the hemicellulose content, and a decrease of 8% in the cellulose concentration compared to the control treatment. The lignin monomers had linear increases in the syringyl:guaiacil ratio. This reflected on significant increases in the concentration of the non-fibrous carbohydrates and the A + B1 fraction of the carbohydrates, and a reduction in the C fraction. The in vitro gas production increased, the time of colonization and initiation of in vitro fermentation linearly decreased in both silages. The phenolic compounds and the antioxidant capacity increased linearly with the addition of the enzymes in both silages. The addition of the lignocellulolytic enzymes to the silages caused changes in the cell wall, resulting in improvements in the in vitro fermentative parameters, besides the additional effect on the antioxidant capacity. There was an effect of the addition of the enzymes on the evaluated fodder, and the best concentration was, on average, 20 mg kg-1 MN for corn silage and 10 mg kg-1 NM for sugarcane silage.

Effect of yerba mate (Ilex paraguariensis A. St.-Hil.) addition on the functional and technological characteristics of fresh cheese.

Milk components have the ability to interact with functional compounds, such as polyphenols. This may result in altered biological activity of the compounds, and changes in the technological properties of dairy products. The objective of this study was to examine the effect of the addition of yerba mate (YM) on the physico-chemical and sensory properties of fresh cheese (FC) during storage (21 days). Different concentrations of YM were used for FC production: 0.0% (control), 0.5% (FC5), 1.0% (FC10) and 2.0% (FC20); and the bioactive compound concentration, antioxidant activity, color, texture, structure and sensory acceptance were evaluated. YM conferred antioxidant activity to FC; and affected the color, texture and structure. Storage time influenced all evaluated parameters except for color. FCs with 0.5 and 1.0% YM were scored as having higher sensory acceptability than FC with 2.0% YM. However, all supplemented FCs were well accepted by consumers (scores above 6). The YM could represent a source of bioactive compounds to improve the biological activity of dairy products.

Quality and sensory acceptability of fish fillet (Oreochromis niloticus) with alginate-based coating containing essential oils.

The quality and sensory acceptability of fish fillet (Oreochromis niloticus) with alginate-based coating containing ginger and oregano essential oils (EO) were evaluated. The antioxidant activity of essential oil, coating, and fish were also investigated. In relation to lipid oxidation, a decrease was observed in fish with the edible coatings compared to the control being the coating with oregano EO the most effective and also with the highest antioxidant activity. Loss in color and weight were significantly lower with coating. Fish with coating maintained firmness whereas fish without coating became softer. Fish with edible coating and oregano essential oils showed higher sensory acceptability regarding to odor evaluated by consumers. Thus, edible coatings with essential oils as natural antioxidant improved the product quality and sensory acceptability.

Effects of blackberries (Rupus sp.; cv. Xavante) processing on its physicochemical properties, phenolic contents and antioxidant activity.

Beneficial health effects are attributed to the wide array of polyphenols such as anthocyanins present in berries. Blackberries have been improved genetically to be cultivated in different climate such as Brazil. Thus, distinctive cultivars were created. However, antioxidant properties of these have not been evaluated. This study aimed to investigate the availability of phenolic compounds in Brazilian cultivar blackberries (cv. Xavante) after processing into purées, coulis and jam changes during storage. Physicochemical, total phenolic compounds (TPC), anthocyanins and antioxidant activity of frozen and processed food products were evaluated. The pH values of jam and frozen pulp increased to a greater extent during storage. Pureé A (70 °C for 20 min) showed the highest value for lightness and redness on day 1 with a decrease after 30 days of storage. Redness values decreased to a greater extent for purée A, indicating less stable product over time whereas coulis presented optimal stability shown by the smaller color difference value. No differences in TPC were observed for frozen pulp, purée A, purée B, and coulis. Significantly lower amount of TPC was present in the jam indicating degradation of phenolic compounds upon heating and concentration process involved in jam making. An increase in antioxidant activity (ABTS assay) was observed in processed products after storage, which might be related to the development of new compounds with greater antioxidant activity. Therefore, processing of blackberries into food products is an alternative to prolong the accessibility of those fruits without extensive loss of antioxidant activities.

Okara residue as source of antioxidants against lipid oxidation in milk enriched with omega-3 and bioavailability of bioactive compounds after in vitro gastrointestinal digestion.

The residue from soy processing (okara) was evaluated for phenolic compounds, flavonoids, radical scavenging activity and reducing power ability. The ability of okara to decelerate the oxidation of omega-3 fatty acids caused by light exposure in a milk matrix, as well as its bioavailability after in vitro digestion, were investigated. Okara contained phenolic compounds (106.7 mg gallic acid equivalents (GAE)/100 g) and flavonoids (32.7 mg quercetin equivalents/100 g) and showed antioxidant activity. The addition of okara to omega-3 fatty acids-enriched milk inhibited the production of conjugated dienes and malonaldehyde during 8 days of storage compared to the control (without okara), particularly at the higher (3 g/L) than lower inclusion concentrations studied (1 and 2 g/L). The bioavailability assay demonstrated that polyphenols (41 mg GAE/100 g) were still present after in vitro digestion and had antioxidant activity. Okara, which is considered a residue and is discarded, can potentially be used as an antioxidant ingredient for the enrichment of foods.

Physical, microbiological and rheological properties of probiotic yogurt supplemented with grape extract.

In this study, yogurt was supplemented with 1.5 and 3.0 g L-1 of grape extract, inoculated culture containing Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus and Bifidobacterium bb12 bifidum, fermented and stored at 4 °C. Acid production, microbial growth, gel strength, syneresis, rheological and sensory properties were studied. An increase in grape extract concentration extended fermentation time. Bacterial strains were found in at least 109 CFU100 g-1 of yogurt showing the possibility of probiotic yogurt production with grape extract. Gel strength decreased with increasing concentration of grape extract while syneresis increased. The addition of grape extract changed the dilatant behavior to a pseudoplastic behavior, decreased yield stress, whereas k values increased. Sensory attributes (color, flavor, taste, texture and appearance) didn't differ significantly.

Effects of storage time and temperature on lipid oxidation of egg powders enriched with natural antioxidants.

The lipid fraction of egg powder may be affected by storage conditions due to the development of oxidative rancidity caused by polyunsaturated fatty acids. This study evaluated egg powders enriched with antioxidants [tocopherol, catechin, lycopene, and butylated hydroxyanisole (BHA)] for conjugated dienes (during a 90-day period) and for malonaldehydes (during a 210-day period) at 25±2 and 4±1°C. The presence of lycopene and BHA increases the total phenolic compounds in the enriched egg powders, and BHA exhibits the most antioxidant activity, as quantified by an ABTS assay. Egg powders enriched with antioxidants do not show any reduction in conjugate diene production compared to controls, and no effect of storage temperature is observed; however, in the production of malonaldehyde, greater stability is observed at 4°C, and catechin is more effective in reducing oxidation during storage. The results show that natural antioxidants can be used in egg powder instead of synthetic compounds to reduce malonaldehyde production during storage.

Production, Composition, Fatty Acids Profile and Stability of Milk and Blood Composition of Dairy Cows Fed High Polyunsaturated Fatty Acids Diets and Sticky Coffee Hull

Four lactating Holstein cows were assigned to a 4 × 4 Latin square design to determine the effects of feeding sticky coffee hull (SCH) as a source of antioxidants on dairy cows fed with high PUFA diets. The treatments (on DM basis) were control diet, diet with 30 g/kg of soybean oil, diet with 30 g/kg of soybean oil and 100 g/kg of SCH, and diet with 30 g/kg of soybean oil and 150 g/kg of SCH. Inclusion of 150 g/kg of SCH decreased the crude protein digestibility. Lower values of NDF digestibility were also observed when cows were fed with 100 g/kg and 150g/kg of SCH. The digestibility of NDT was lower in the control and 150 g/kg of SCH diets. Milk production and composition did not differ among the treatments. Inclusion of SCH increased the total polyphenols and flavonoids in the milk and reducing power as well. Soybean oil and SCH supplementation increased the LDL and total cholesterol concentration in the plasma. Milk fatty acid profile was barely altered by the treatments. In conclusion, the results confirmed that SCH added up to 15% in the diet did not alter milk production, improved its stability, and incorporated antioxidants substances in the milk, improving its quality for human health.