Sylvio V. Palombini

Evaluation of nutritional compounds in new amaranth and quinoa cultivars

This study evaluated the fatty acid quantification, proximate and amino acid compositions, antioxidant activity, total phenolic compounds, vitamin E, and mineral contents of new amaranth (BRS Alegria) and quinoa (BRS Piabiru) cultivars which were produced in order to adapt these pseudocereals to the climatic conditions of central-western Brazil. They showed superior levels of protein and total lipids in comparison to their native counterparts. The lipid profile of the amaranth BRS Alegria was revealed to be better than those of other native cultivars. Quinoa BRS Piabiru presented a higher antioxidant capacity and phenolic content than the studied amaranth cultivar, but lower contents of tocopherols. All of the obtained results confirm that these new grains possess an overall amount of nutritional compounds that is better than those reported for many native counterparts of the studied samples. The employed analytical methods in this work contributed to a better understanding of the quinoa BRS Piabiru and amaranth BRS Alegria chemical compositions. Therefore, the diversity and quantity of all of the studied compounds in the samples denote the considerable importance of these grains for food science research area.

Evaluation of antioxidant potential of Brazilian rice cultivars

This study quantified the fatty acids and evaluated the proximate composition, antioxidant activity (using the Quencher procedure), and total phenolic compound concentrations in Brazilian rice cultivars. The cultivars studied showed high amounts of unsaturated fatty acids, such as linoleic and oleic acid. The ratios of polyunsaturated and saturated fatty acids obtained were high. Regarding the antioxidant activity, the best results were found using the ABTS method and the worst in the DPPH assay. The results of the DPPH and FRAP assays showed the highest correlation. The antioxidant capacity results obtained were also much higher than those reported for other varieties worldwide. Therefore, the Quencher procedure is highly suitable for application in cereals such as rice, especially when combined with the ABTS radical capture method.

Antioxidant Activity of Brazilian Bean Cultivars

This study quantified fatty acids and evaluated the proximate composition, antioxidant activity paired with Quencher procedure and total phenolic compounds in Brazilian bean cultivars. The samples showed high amounts of polyunsaturated fatty acids, such as linoleic acid (191.54 to 329.50 mg g-1 of total lipids) and α-linolenic acid (228.03 to 367.27 mg g-1 of total lipids). The obtained ratios between Omega 6 and 3 fatty acids were low, between 0.71 and 1.12. In relation to antioxidant activity assays, the cultivars showed the best results upon employing the 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) method (2401.34 to 4394.80 µmol Trolox equivalent g-1). The lowest results were observed in the ferric reducing antioxidant power (FRAP) assays, 530.93 to 1440.13 µmol Trolox equivalent g-1. The results from 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS methods showed the greatest correlation between themselves (r = 0.619). High concentrations of total phenolic compounds were also detected in the studied cultivars, which varied from 81.85 to 173.65 mg gallic acid equivalent 100g-1.

Application of box-behnken design to the study of fatty acids and antioxidant activity from enriched white bread

This work determined the proximate/fatty acid composition and the antioxidant activity of breads using a Box-Behnken design composed of fifteen experiments and three factors. The studied breads had altered baking times and the wheat flour was partially substituted by chia seeds and carrot leaves. Total antioxidant capacity results were superior to those obtained from control bread (495.33 µmol TEAC g-1 for DPPH assays and 413.85 µmol TEAC g-1 for FRAP assays), showing increased levels of 97 and 102% for DPPH and FRAP assays, respectively. The addition of chia seeds and carrot leaves led to maximal alpha-linolenic acid increase of 216.69% and maximum PUFA:SFA ratio increase of 18.88% in relation to control bread (this with alpha-linolenic acid amount of 34.03 mg g-1 total lipid and a 2.86 ratio value), as well as a maximum omega-3:omega-6 ratio reduction of 70.01% (15.59 ratio value for control bread).

Optimization of a New Methodology for Determination of Total Phenolic Content in Rice Employing Fast Blue BB and QUENCHER Procedure

Response surface methodology was used to optimize the total phenolic content (TPC) result in white rice, using a new methodology that employed Fast Blue BB (FBBB) reagent, which reacts more specifically with phenolic compounds, along with direct QUENCHER procedure. This is the first time in which such conciliation between FBBB reagent and QUENCHER was done. The obtained model allowed to evaluate how the factors influenced the method linearity (R2), improving the choice of the optimal system condition. Furthermore, the similarity between experimental results and values generated by the model indicated the method validity within the studied region. Thus, the optimal condition determined in the present work was 30 min reaction time, 0.17 mL FBBB reagent and use of 5% NaOH as the catalyst for the reaction. This optimized condition suggested that the combination of the method, which used FBBB reagent and the direct QUENCHER procedure, was rapid and effective, yielding high TPC values (1488.73 mg of gallic acid equivalent per 100 g).

Antioxidant capacity in tilapia fillets enriched with extract of acerola fruit residue

This work evaluated the effect of supplementation with ethanolic extract of acerola fruit residue (EEAR) on the antioxidant capacity of tilapia fillets over a period of 60 days. Different methodologies were used following the QUENCHER procedure, and the hydrophilic and lipophilic fractions of the oxygen radical absorbance capacity (ORACFL) assay were analysed. The fatty acid composition was also evaluated, as high concentrations of linoleic and oleic acids were observed in the fillets, as well as satisfactory polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) ratios. The highest antioxidant capacities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays (1778.87 and 4892.77 µmol Trolox equivalent antioxidant capacity (TEAC) g-1, respectively) were found at 15 days, and these trials showed the highest correlation coefficient (R = 0.9388). The ORACFL assay indicated that the hydrophilic fraction is the largest contributor to the total antioxidant capacity (TAC). Thus, the significant increase observed in antioxidant capacity makes supplementation with EEAR a potent tool in the elevation of the antioxidant capacity of tilapia fillets.

Investigation of Distribution of Antioxidant Compounds from Natural Sources and Study of Lipid Protection in Oil-in-Water Emulsions

The investigation of the distribution of antioxidant compounds between emulsions phases, employing natural sources of these compounds directly in the emulsions, is rarely addressed. The use of ultra performance liquid chromatography coupled to a mass spectrometer (UPLC-MS), combined with accelerated oxidation tests and oxygen radical absorbance capacity method (ORAC), using the fluorescein (FL) decay curve (ORACFL) assay, enable an improved evaluation of the distribution of the antioxidant compounds and their lipid protection abilities. The lipid protection tendency observed was in agreement with the polar paradox theory. The ORACFL results reported here are higher than other reported in the literature, even when performing a sample extraction directly into one of the emulsion phases, thus demonstrating the effectiveness of this direct addition regarding the antioxidant activity. The analysis of the mass spectra of the emulsions enabled to verify the existence and distribution of some phenolic compounds in both phases. The direct extraction in the aqueous and oil phases of the emulsion increased, in a general way, the amount of identified compounds in each phase.

Simultaneous Determination of Four Antibiotics in Raw Milk by UPLC-MS/MS Using Protein Precipitation as Sample Preparation: Development, Validation, and Application in Real Samples

In this study, a rapid and simple analytical method was proposed, based on protein precipitation as sample preparation for simultaneous determination of tetracycline, oxytetracycline, penicillin G and ceftiofur in raw milk by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The method was applied to raw milk samples from dairy cows medicated with tetracycline for subclinical mastitis. Samples were collected from the adjacent teat to the teat treated with tetracycline of eight different cows at 24, 48, 72 and 96 h after treatment. The limits of quantification of the proposed method ranged between 1 and 5 ng g and limits of detection ranged between 0.1 and 0.5 ng g. The recoveries ranged from 61 to 111% and the linear range was 1 to 2064 ng g for tetracycline and oxytetracycline, and 5 to 2064 ng g for penicillin G and ceftiofur. Approximately 75 and 63% of the treated animals revealed more tetracycline than legally recommended at 72 and 96 h since last treatment, respectively.

Response Surface Methodology Applied in the Study of Emulsion Formulations in the Presence of Leaves of Rosemary (Rosmarinus officinalis L.) as a Source of Natural Antioxidants

The use of synthetic antioxidants in human consuming products is in disuse due to health toxic related issues. The search for substances to substitute synthetic antioxidants boosts studies concerned with the findings of sources of natural antioxidants. Thus, the aim of this work was to evaluate the use of comminuted leaves of rosemary (Rosmarinus officinalis L.) as source of natural antioxidants for the lipid protection of different emulsion compositions using central composite rotary experimental design. The Oxitest analysis (oxidation test reactor) revealed rosemary to be an excellent source of antioxidants for emulsions, even with addition of low quantities, and the gain of induction point tripled. The oxygen radical absorbance capacity (ORACFL) results of emulsion obtained separately for the hydrophilic and lipophilic phases showed that the presence of polar compounds was in higher concentration, about 500 more than of non-polar ones. The polar compounds are major responsible for the antioxidant action in the system.

A Prompt, Tough and Eco-Friendly (PTOCO) System for Mini-Scale Extraction of Samples for Antioxidant Capacity Assays

The compound extraction is an important step before analyzing composition of samples with antioxidant capacity. Several extraction conditions can be employed (temperature, polarity of solvent and extraction time, for example), and the chosen variables exert great influence upon final results. Thus, in order to execute an efficient extraction, it is needed to manage them with rigor. In this work, a new device was designed and tested. The Prompt, TOugh and eCO-friendly (PTOCO) system is the first equipment in mini-scale that allows a good control of antioxidants extraction conditions. It is a simple and cheap device that only needs small amounts of sample and solvent to obtain sufficient volumes of extract for application in routine analytical methods. Twenty experiments from an experimental design were executed using only 0.5 g of oregano and 60 mL of water. The total antioxidant capacity assays, as well as the mass spectra, confirmed the extraction efficiency.