Thiago Claus

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.

Analysis of carotenoids, α-tocopherol, sterols and phenolic compounds from white bread enriched with chia (Salvia hispanica L.) seeds and carrot (Daucus carota L.) leaves

Each food matrix is unique. Thus, the endogenous antioxidants of an underexplored bakery product might show different responses regarding free radical scavenging/resistance to forced oxidation than what is expected for other foods previously reported in the literature. In this context, a Box-Behnken design and correlation studies were applied in order to obtain more information about how specific antioxidants affect the total antioxidant activity (TAC) and the degree of forced oxidation in white breads with chia seeds and carrot leaves. Hypotheses of synergism/antagonism between the studied compounds were also elucidated in order to justify the obtained results. In this specific sample type, carotenoids and cholesterol showed the greatest relationships with results from TAC assays, as well with induction points using Oxitest® equipment, while α-tocopherol and phytosterols showed negative correlations. Phenolic compounds did not have any influence on the system because the baking procedure at high temperature had severe impacts on them.

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).

Rapid methodology via mass spectrometry to quantify addition of soybean oil in extra virgin olive oil: A comparison with traditional methods adopted by food industry to identify fraud

Fast and innovative methodology to monitors the addition of soybean oil in extra virgin olive oil was developed employing ESI-MS with ionization operating in positive mode. A certified extra virgin olive oil and refined soybean oil samples were analyzed by direct infusion, the identification of a natural lipid marker present only in soybean oil (m/z 886.68 [TAG+NH4]+) was possible. The certified extra virgin olive oil was purposely adulterated with soybean oil in different levels (1, 5, 10, 20, 50, 70, 90%) being possible to observe that the new methodology is able to detect even small fraud concentration, such as 1% (v/v). Additionally, commercial samples were analyzed and were observed the addition of soybean oil as a common fraud in this segment. This powerful analytical method proposed could be applied as routine analysis by control organization, as well as food industries, considering its pronounced advantages; simplicity, rapidity, elevated detectability and minor amounts of sample and solvent consumed.

Fast derivatization of fatty acids in different meat samples for gas chromatography analysis

In order to analyze the composition of fatty acids employing gas chromatography as the separation method, a derivatization of lipids using esterification and transesterification reactions is needed. The methodologies currently available are time consuming and use large amounts of sample and reagents. Thus, this work proposes a new procedure to carry out the derivatization of fatty acids without the need for prior extraction of lipids. The use of small amounts of sample (100mg) allows the analysis to be performed in specific parts of animals, in most cases without having them slaughtered. Another benefit is the use of small amounts of reagents (only 2mL of NaOH/Methanol and H2SO4/Methanol). The use of an experimental design procedure (Design Expert software) allows the optimization of the alkaline and acid reaction times. The procedure was validated for five minutes in both steps. The method was validated for bovine fat, beef, chicken, pork, fish and shrimp meats. The results for the merit figures of accuracy (from 101.07% to 109.18%), precision (RSDintra-day (from 0.65 to 3.93%), RSDinter-day (from 1.57 to 5.22%)), linearity (R(2)=0.9864) and robustness confirmed that the new method is satisfactory within the linear range of 2-30% of lipids in the sample. Besides the benefits of minimizing the amount of samples and reagents, the procedure enables gas chromatography sample preparation in a very short time compared with traditional procedures.

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.

Incorporation and profile of fatty acids in tilapia fillets (Oreochromis niloticus) fed with tung oil

The acceptance of tung oil enriched diet and the incorporation of conjugated linolenic acid - CLnA into fillets of Genetically Improved Farmed Tilapia (GIFT) were investigated. The diet was well accepted, and after 10 days CLnA was incorporated into the fillets with a 1.02% content of total fatty acids (FA). In addition, biosynthesis of the conjugated linoleic acid isomers - CLA (0.31% of fillet total FA content) from CLnA, and the presence of alpha-linolenic acid - LNA (1.08% of fillet total FA content), eicosapentaenoic acid - EPA (2.85% of fillet total FA content) and docosahexaenoic acid - DHA (3.08% of fillet total FA content) were observed. Therefore, the consumption of this fish can increase the intake of different FA (CLnA, CLA, LNA, EPA and DHA), which play an important role in human metabolism.