Antioxidant capacity of amaranth products: effects of thermal and enzymatic treatments

The effect of different process -defatting, protein concentration, thermal treatment, hydrolysis with Alcalase and in vitro digestion- on the antioxidant capacity of amaranth seeds was studied. The antioxidant capacity of the products was determined in methanolic and aqueous extracts and varied from 1.00 to 21.22 and 4.97 to 369.18 µ mol TE/g sample for DPPH and ORAC assays, respectively. The combination of protein concentration and hydrolysis with Alcalase led to products with higher antioxidant activity. However, after in vitro digestion, protein concentrate and its hydrolysate showed similar antioxidant capacity. A high correlation was observed between the antioxidant capacity and the total phenolic content for methanolic extracts, with r² values ranging from 0.6133 to 0.9352.

Antioxidant capacity and chemical composition in seeds rich in omega-3: chia, flax, and perilla

The chemical composition and antioxidant capacity of five seeds, chia, golden flax, brown flax, white perilla, and brown perilla, were determined. The chemical properties analyzed included moisture, ash, crude protein, carbohydrates, total lipids, fatty acids, and antioxidant capacity (ABTS•+, DPPH•, and FRAP). The results showed the highest amounts of protein and total lipids in brown and white perilla. Perilla and chia showed higher amounts of alpha-linolenic fatty acid than those of flaxseed varieties, ranging between 531.44 mg g-1 of lipids in brown perilla, 539.07 mg g-1 of lipids in white perilla, and 544.85 mg g-1 of lipis in chia seed. The antioxidant capacity of the seeds, evaluated with ABTS•+, DPPH• , and FRAP methods, showed that brown perilla had greater antioxidant capacity when compared with white perilla, flax, and chia seeds.

Correlation, by multivariate statistical analysis, between the scavenging capacity against reactive oxygen species and the bioactive compounds from frozen fruit pulps

The contents of total phenolic compounds (TPC), total flavonoids (TF), and ascorbic acid (AA) of 18 frozen fruit pulps and their scavenging capacities against peroxyl radical (ROO•), hydrogen peroxide (H2O2), and hydroxyl radical (•OH) were determined. Principal Component Analysis (PCA) showed that TPC (total phenolic compounds) and AA (ascorbic acid) presented positive correlation with the scavenging capacity against ROO•, and TF (total flavonoids) showed positive correlation with the scavenging capacity against •OH and ROO• However, the scavenging capacity against H2O2 presented low correlation with TF (total flavonoids), TPC (total phenolic compounds), and AA (ascorbic acid). The Hierarchical Cluster Analysis (HCA) allowed the classification of the fruit pulps into three groups: one group was formed by the açai pulp with high TF, total flavonoids, content (134.02 mg CE/100 g pulp) and the highest scavenging capacity against ROO•, •OH and H2O2; the second group was formed by the acerola pulp with high TPC, total phenolic compounds, (658.40 mg GAE/100 g pulp) and AA , ascorbic acid, (506.27 mg/100 g pulp) contents; and the third group was formed by pineapple, cacao, caja, cashew-apple, coconut, cupuaçu, guava, orange, lemon, mango, passion fruit, watermelon, pitanga, tamarind, tangerine, and umbu pulps, which could not be separated considering only the contents of bioactive compounds and the scavenging properties.

Effect of an edible crosslinked coating and two types of packaging on antioxidant capacity of castilla blackberries

In order to increase the shelf life and maintain the quality and stability of the biological compounds with antioxidant activity present in Castilla blackberry fruits, a sodium alginate-based edible crosslinked coating was applied, and the fruits were packed in two different plastic containers and stored under refrigeration (3 ± 1 °C). Total antioxidant capacity and its relationship to physicochemical variables such as pH, Brix, and acidity were evaluated in six treatments: uncoated blackberry stored in a macroperforated container (T1) and thermosealed container (T2), without crosslinked coating in a macroperforated container (T3) and thermosealed container (T4), with crosslinked coating (calcium ions) packed in macroperforated container (T5) and thermosealed container (T6). The results indicated that factors such as gas permeability in the coatings, the packaging used, and physicochemical parameters significantly affected the fruit total antioxidant capacity, with the highest level in T1 (0.22 µgEAA/ml) at the end of the essay, which is related to the lowest levels of pH and direct exposure to air. On the other hand, the lowest value was obtained in T6 (0.16 µgEAA/ml) due to the crosslinked coating, packaging in the thermosealed container, and higher pH value. Variations in acidity, Brix, and pH indicate the presence of degenerative processes in the crosslinked coating treatments, which limited the physicochemical changes.

Chemical composition and effects of micronized corn bran on iron bioavailability in rats

The degermination of corn grains by dry milling generates 5% of a fibrous residue. After segregation and micronization, corn bran becomes a potential source of dietary fiber consumption. However, its effect on iron bioavailability has not been reported in the literature. The objective of the present study was to determine the nutritional composition of corn bran and its effects on iron bioavailability using the hemoglobin depletion-repletion method in rats. The animals were divided into two groups: cellulose (control) and corn bran (experimental). The bran had high content of total dietary fiber, especially the insoluble fraction, and low phytate content. Hemoglobin uptake did not differ between groups at the end of repletion period, and the iron relative bioavailability value of the corn bran diet was 104% in comparison to that of the control group. The product evaluated proved to be a potential source of dietary fiber and it showed no negative effects on iron bioavailability.

Nutritional value and antioxidant capacity of "cocoa honey" (Theobroma cacao L.)

Cocoa honey is considered as the liquid portion of cocoa pulp that is released from the fruit soon after it is cut open and can be used before fermentation by simple extraction due to its nutritional characteristics. The objective of the present study is to determine the biochemical characteristics of a cocoa by-product, "cocoa honey" (CH), produced in the State of Bahia-Brazil. The biochemical characterization was conducted to determine reducing sugars, total sugars, vitamin C, total dietary fiber, flavonoids, and total antioxidant activity using an EC50. It was observed that cocoa honey can be considered a source of bioactive compounds, can be consumed in natura or processed, and used as an ingredient in the chocolate industry and in other food products. However, it is necessary to use complementary methods, such as HPLC, to quantify the phenolic compounds of this by-product.

Screening of iron-enriched fungus from natural environment and evaluation of organically bound iron bioavailability in rats

Iron is an essential element for nearly all living organisms, and its deficiency is the most common form of malnutrition in the world. The organic forms of trace elements are considered more bioavailable than the inorganic forms. Although Saccharomyces cerevisiae can enrich metal elements and convert inorganic iron to organic species, its tolerability and transforming capacity are limited. The aim of this study was to screen higher biomass and other iron-enriched fungi strains besides Saccharomyces cerevisiae from the natural environment. A PDA medium containing 800 μg/mL iron was used for initial screening. Fifty strains that tolerated high iron concentration were isolated from the natural environment, and only one strain, No.BY1109, grew well at Fe (II) concentration of 10,000μg/ml. According to morphological characterization, 18S rDNA sequence analysis, and biophysical and biochemical characterization, the strain No.BY1109 was identified as Rhodotorula. The iron content of No.BY1109 (10 mg Fe/g dry cell) was determined using atomic absorption spectrometry. The results of distribution of iron in the cells showed that iron ion was mainly chelated in the cell walls and vacuoles. The bioavailability in rats confirmed that strain No.BY1109 had higher absorption efficiency than that of ferrous sulfate after single dose oral administration. The present study introduces new iron supplements, and it is a basis for finding new iron supplements from natural environment.

Nutritional quality and bioactive compounds of partially defatted baru almond flour

This study aimed to investigate the nutritional quality and bioactive potential of partially defatted baru (Dipteryx alataVog.) almond flour (BAF). The flour’s proximate and mineral compositions, total phenolic, tocopherols and carotenoids contents, antioxidant capacity, trypsin inhibitor and amino acid analyses were performed. An experiment was conducted with 24 male Wistar rats in order to evaluate the flour’s protein quality. BAF has high protein, fiber and mineral contents (iron, zinc, magnesium and copper), and it is a source of calcium. BAF presented relevant amounts of total phenolics (625 mg/100g) and good antioxidant capacity (130 µmol/Trolox eq). Autoclaved BAF showed essential amino acids profile, digestibility and protein quality better than in natura BAF. Autoclaved BAF might be used for human consumption as a source of quality protein and bioactive compounds, in healthy diets and processed foods.

Phenolic content and antioxidant capacity in organically and conventionally grown eggplant (Solanum melongena) fruits following thermal processing

AbstractThermal processing and production practices used in vegetables can cause changes in their phytochemical contents. Eggplant is characterized by its high antioxidant content. The objective of this work was to determine levels of anthocyanins, polyphenols, and flavonoids and antioxidant capacity in organically and conventionally grown eggplant prepared fresh or subjected to one of three thermal preparation methods: boiling, baking or steaming. The soluble and hydrolyzable polyphenols and flavonoids content were quantified by Folin-Ciocalteu and Aluminum chloride methods, respectively. Anthocyanins were quantified according to the pH differential method. Antioxidant capacity was determined by DPPH and ORAC methods. The results showed differences between organic and conventional eggplant for some variables although cultivation method did not have a consistent effect. Hydrolysable polyphenol content was greater, and soluble and hydrolysable antioxidant capacities were higher in organically grown eggplant, while anthocyanin content was greater in conventionally grown eggplant. Fresh eggplant produced under conventional cultivation had a much greater content of anthocyanins compared to that of other cultivation method-thermal treatment combination. In general, steamed eggplant contained higher total polyphenol and flavonoid levels as well as greater antioxidant capacity. Steamed eggplant from both conventional and organic systems also had high amounts of anthocyanins compared to other thermal treatments.