Mangos (Mangifera indica L.) are tropical/subtropical fruits belonging to the plant family Anacardiaceae. Anthracnose is the most deleterious disease of mango both in the field and during postharvest handling. It is most commonly caused by the Colletotrichum gloeosporioides complex. Mangiferin, a xanthanoid compound found in at least twelve plant families worldwide (Luo et al., 2012), is present in large amounts of the leaves and edible mangos. Even though this compound plays a pivotal role in the plant’s defense against biotic and abiotic stressors, no correlations been made between the compound and mango anthracnose resistance. Mangos were collected, grouped according to their countries of origin, and evaluated for their mangiferin concentrations at four different stages of development. Extracts of interest were then tested against different strains of C. gloeosporioides. The results demonstrated that mangiferin concentrations are significantly different at different stages in fruit development. The antifungal assays were inconclusive.

Foi estudada a fração não-protéica de sementes de feijão (Phaseolus vulgaris L. ), tendo por objetivo identificar a presença e conhecer o teor de (γ-glutamil peptídeos sulfurados. Estes peptídeos (γ-glutamil-S-metilcisteína e (γ-glutamil metionina) podem interferir com o doseamento da metionina pelo método da clivagem com brometo de cianogênio e análise do metiltiocianato por cromatografia em fase gasosa. O extrato etanólico contém 21 % do nitrogênio total do feijão. A lavagem do extrato com clorofórmio reduziu o teor de nitrogênio para 5,5%, pela remoção de proteínas co-extraídas. O extrato não-proteico assim obtido foi purificado sucessivamente por resinas de troca catiônica e aniônica, ocorrendo a separação dos constituintes pelos seus valores de pK. A purificação foi acompanhada por testes químicos, cromatografia em camada delgada e análise de aminoácidos. Foi identificada com base nas suas características químicas, a presença de S-metilcisteína, principalmente na forma de dipeptídeo com ácido glutâmico. A quantificação do peptídeo após hidrólise ácida (3h / 110° C), resultou num teor de S-metilcisteína total de 0,67g /100g proteína, que corresponde a aproximadamente 50% do teor de metionina no feijão, determinado por cromatografia de troca iônica. Estes resultados podem indicar que o teor de metiltiocianato total, liberado pela metionina e pela S-metilcisteína do feijão (1 ,6%) (determinado em trabalho anterior), descontado do teor de S-metilcisteína (0 ,7%), equivale à metionina quimicamente disponível, correspondendo a aproximadamente 64% da metionina total presente no feijão. No ensaio de germinação das sementes do feijão foi observado um decréscimo da (γ-glutamil-Smetilcisteína, indicando uma mobilização dos aminoácidos constitutintes. / The non-protein fraction of Phaseolus vulgrias L. seeds has been analysed to obtain information on the identity and level of (γ-glutamyl peptides containing a sulfur amino acid. These peptides (γ-glutamyl-S-methylcysteine and (γ-glutamyl methionine) could interfere with the determination of methionine measured by cleavage with cyanogen bromide and subsequent gas-chromatographic identification of methylthiocyanate. The ethanolic extract of (γ-glutamyl peptides contains 21% of the total seed nitrogen, which decrease to 5,5%, by removing the coextracted bean proteins with chloroform. This non-protein extract was then purified by ion-exchange chromatography on basic and acid resins, taking advantage of the different pK values of the amino acids. The isolation procedure was followed up by chemical analysis, thin layer chromatography and amino acid analysis. Based on their chemical properties we were able to identify the presence of S-methylcysteine, mainly in the form of a dipeptide with glutamic acid. Quantitative analysis of the peptide after acid hydrolysis (3h /110° C) showed a level of 0,67g /total S-methylcysteine /100gbean protein. This content accounted for approximately 50% of the bean methionine content, determined by ion-exchange chromatography. These results might indicate that total methylthiocyanate released from both, methionine and S-methylcysteine of beans, (1,6%) (from a previous paper) subtracted from S-methylcysteine (0,7%) could be recognized as chemically available methionine, corresponding to approximately 64% of total methionine. During seed germination the (γ-glutamyl-S-methylcysteine undergo a degradative process resulting in loss of the dipeptide.

A qualidade da carne envolve aspectos estéticos, avaliados pelo consumidor e físico-químicos importantes para o processador, os quais podem ser controlados nas diversas etapas de produção. Na primeira fase, a fim de determinar a qualidade de carcaças e cortes aplicou-se um sistema de classificação, os quais foram avaliados na aparência (conformação, conteúdo de carne, cobertura de gordura, depenagem, carne exposta e corte, ossos quebrados, descolorações e hematomas) e classificados em níveis A, B ou C, decrescendo de nível conforme os defeitos se apresentaram, além analisou-se a capacidade de retenção de água (CRA), para esta fase utilizou-se à análise discriminante e análise de variância. Na segunda fase, foram avaliados os atributos de qualidade (cor, pH, CRA, força cisalhamento, perda de peso por cozimento, composição centesimal, análise sensorial) dos cortes de peito, coxa e sobrecoxa às 5, 24, 48 e 72 horas pós abate, para frangos criados no sistema alternativo. Para análise dos resultados foram utilizadas as análises de médias, regressão múltipla, correlação simples de Pearson e correspondência para os atributos físico-químicos e sensoriais. Na classificação foram avaliadas 301 carcaças e 146, 147 e 145 de cortes de peito, coxa e sobrecoxa respectivamente. Das carcaças analisadas, 79,73% apresentaram algum grau de contusão, sendo que 65,78% destas eram de grau leve, dessa forma, foram classificadas como tipo A. Fazendo uso da análise discriminante, 84,9% das carcaças mostraram-se corretas quanto à classificação utilizada, apresentando diferença significativa entre as classes. Os outros defeitos foram arranhões, corte de pele, depenagem, resíduo de pele, fraturas ou ossos quebrados. Quanto aos cortes (peito, coxa e sobrecoxa), a maioria foi classificada na categoria A. Os cortes de peito, coxa e sobrecoxa apresentaram 87,7, 96,2 e 95% das amostras corretamente classificadas, respectivamente. Foi realizada na análise de CRA para peito e coxa, observando-se que o corte da coxa classificada como A apresentou maior valor de CRA comparada com o tipo C. Na avaliação da qualidade dos cortes de peito, coxa e sobrecoxa, verificou-se o comportamento da carne nas características físico-químicas em quatro períodos distintos: 5, 24, 48 e 72 horas após o abate. Com o decorrer do tempo de maturação, no peito observou-se um aumento no valor de L* e um decréscimo da força de cisalhamento da carne de peito, melhorou a qualidade promovendo um amaciamento da carne, entretanto, para a coxa não apresentou mudanças na qualidade com o decorrer do tempo, apenas foi observado um acréscimo no valor a*, porém a sobrecoxa a partir de 48 horas, os efeitos da proteólise do músculo influenciaram um aumento significativo na perda de peso inversamente ao CRA. Quanto à análise sensorial, não houve diferença entre o frango alternativo e convencional e nem entre as horas pós abate para os três cortes. Também foram realizadas as análises de correlação simples de Pearson e correspondência para os atributos físico-químicos e sensoriais. / Meat quality is related to a esthetical aspects, which are evaluated by the consumer, and to physiochemical aspects, which are important to the meat processor. These aspects can be controlled at the various steps during production. In the first phase of this study, aiming at evaluating carcasses and cuts, a grading system was used by which meat appearance (conformation, fleshing, fat covering, feathers, exposed flesh and cuts, broken bones, skin discoloration and bruises) was evaluated. They were grading in A, B and C class, according to defects, besides analyzing a water holding capacity (WHC), in this phase a discriminant and variance analyses were utilized. In the second phase, the attributes quality (colour values, pH, WHC, shear force, cooking loss, chemical composition, sensory analyses) of breast, drumstick and thigh cuts, from chicken raised in natural system, was evaluated 5, 24, 48 and 72 hours after slaughtering. In order to analyze the results, the following were used: analysis of means, multiple regression, Pearson’s simple correlation and the relationship with the physicochemical and sensorial parameters. At grading, a total of 301 carcasses and 146,147 and 145 breasts, drumsticks and thigh broilers, respectively, were evaluated. The results indicated that 79, 73% of the carcasses contained some degree of bruise and that 65, 78% contained light bruise, thus being classified as class A. Results of the discriminant analysis showed that 84,9% of the carcasses was correctly graded, showing significant difference among the classes. Other defects found were scratches, skin cuts, feathers and skin residue, fractured and broken bones. Breast, thigh and drumstick cuts had 87,7, 96,2 and 95,0% of samples correctly graded, respectively. A C analysis was done for breast and drumstick, showing that the drumstick classified as class A had a higher WHC value compared to class C. At the breasts, drumsticks and thigh broilers evaluation, the physiochemical behavior of the meat was studied in four different periods: 5, 24, 48 and 72 hours after slaughtering. During the aging period, an increase in the L+ value and a decrease in the shear force of the breast meat were observed, resulting in a quality improvement by meat softening. The drumstick did not show changes in quality, and only an increase in the value a* was observed. However, the thigh showed a significant increase on the weight loss inversely to the WHC, due to the effects of the muscle proteolysis. The sensorial analysis for the three cuts no significant difference between both the natural and conventional chicken and the time after slaughtering was observed.

<div> <p>Chia seed (<i>Salvia hispanica</i>) has shown potential as an alternative source of nutrients with a high content of fiber (36 %), protein (25%), and fat (25%). Unfortunately, the presence of a viscous biopolymer (mucilage), surrounding the chia seed (CS), limits the accessibility of the protein and other nutrients. Nevertheless, this biopolymer’s chemical composition makes it suitable for the development of biodegradable films. Regarding CS protein, disulfide bonding, and nonprotein-protein interactions often frequent in plant protein, have limited its technological application in food matrices. Therefore, scientists have pointed at processing methods involving enzymatic proteolysis to improve the functionality of plant protein ingredients. The objective of this study was to establish processing techniques to exploit the functionality, extraction, and health benefits of chia seed components. First, ultrasonication followed by vacuum-filtration was used to separate mucilage from CS prior to fat extraction by oil press. Mucilage-free and defatted CS were treated using conventional (enzymatic hydrolysis with alcalase) or sequential (enzymatic hydrolysis with alcalase+flavourzyme), and under water bath or microwave-assisted hydrolysis. Chia seed protein hydrolysates (CSPH) derived from the sequential hydrolysis with microwave treatment showed superior (p<0.05) in vitro antioxidant activity. The highest (p<0.05) cellular antioxidant activity was achieved by the sequential (94.76%) and conventional (93.13%) hydrolysis with microwave. Dipeptidyl peptidase-V inhibition was higher (p<0.05) for sequential hydrolysis with water bath, while Angiotensin-Converting Enzyme (ACE) inhibition activity increased (p<0.05) with hydrolysis for all treatments compared to the control. Regarding functionality, sequential hydrolysis with microwave showed higher (p<0.05) solubility at lower pH (3 and 5), while conventional hydrolysis with microwave was better at pH 7 and 9. Emulsification properties and foaming capacity were also higher in conventional hydrolysis with microwave, but conventional hydrolysis with water bath was more stable for foaming properties only. In terms of mucilage applicability, biodegradable films were developed by casting technique where CS mucilage was plasticized with different polyol mixtures (sorbitol and glycerol). CS mucilage films with higher sorbitol content showed superior tensile strength (3.23 N/mm²), and lower water vapor permeability (1.3*109 g/ m*s*Pa) but had poor flexibility compared to other treatments. Conversely, films with high glycerol content showed high elongation at break (67.55%) and solubility (22.75%), but reduced water vapor permeability and tensile strength. The hydrophobicity, measured as water contact angle, was higher (p<0.05) for mixtures containing equal amounts of polyols. Lastly, Raman Spectroscopy analysis showed shifts from 854 to 872 cm^-1 and 1061 to 1076 cm^-1, which corresponded to β(CCO) modes. These shifts represent an increase in hydrogen bonding, responsible for the high tensile strength and decreased water vapor permeability. This study demonstrated that ultrasonication followed by vacuum filtration can successfully separate mucilage from chia seeds; microwave-assisted and enzymatic hydrolysis generated protein hydrolysates with improved bioactivity and functionality. Finally, chia seed mucilage was able to form films with potential to be used in drug delivery and edible food coating applications.</p> </div> <br>

The increasing market demand for fresh produce promotes a keen interest in developing a rapid, sensitive and reliable method for monitoring plant health and determining the shelf-life of postharvest produce. The objective of this study is to explore the capability of Surface-enhanced Raman spectroscopy (SERS) in these applications. SERS integrates Raman spectroscopy which measures molecular vibrations and nanotechnology which enhances the weak Raman signals. Herein, we developed two SERS methods based on a surface detection approach using nanoparticles solution and a headspace detection approach using gold nanoparticles (AuNPs) fibers, to detect biochemical changes during postharvest storage of arugula leaves. Compared with surface detection, the headspace detection revealed significant spectral changes during the storage, particularly in the shifts around 500, 950 and 1030 cm-1. These changes analyzed using principal component analysis (PCA) to establish a prediction model for shelf-life determination. Through analyzing reference standard compounds, we identified the dimethyl disulfide (DMDS), 1-propanethiol and methanethiol (MT) were most likely to account for the signature spectra of headspace arugula at the late storage period due to the activities of spoilage bacteria. The headspace detection method was also applied to monitor the stress responses of living basil to abiotic stresses (pesticide/salinity). However, the volatile analysis of the basil plants response to abiotic stresses (pesticide/salinity) showed indistinctive results. In conclusion, the headspace detection based on SERS provides a new strategy for quality monitoring of fresh produce in the food industry.

Extra lean (3.3% fat) and lean (20.0% fat) hamburgers in three pH groups (≤ 6.0; 6.01-6.49; 6.50-6.92) were evaluated for cooking-temperature profile, total process lethality, and physical properties after cooking to 71°C by double-side frying on an electric grill. Neither cooking-temperature profile nor cooking time was affected by hamburger fat content or pH. Double-side frying to 71.1°C internal temperature was adequate for more than 6-log destruction of viable E. coli O157:H7 and Salmonella at the geometrical center of extra lean and lean hamburgers. The coldest spot was on the circumferential surface, as indicated by the presence of a red ring of undenatured myoglobin, and confirmed by the finite-element temperature distribution model. The effect of pH (5.80, 6.29, 6.73) on myoglobin denaturation in extra lean (3.3% fat) and lean (20.0% fat) hamburgers was studied. Compared to normal meat (pH= 5.8), raw extra lean ground beef of pH = 6.73 had significantly lower oxidation-reduction potential (ORP) value, lower concentration of metmyoglobin after 48 hr of refrigerated storage, and more distinct cherry-red color. Percent of myoglobin denaturation during cooking was affected mainly by pH and was not affected by total pigment or fat content of hamburgers. A pH ≥ 6.5 and ORP ≤ -200 mV were characteristic of dark-cutting beef In a third experiment, extra lean (3.5%) and lean (20.0%) beef patties were made from normal beef (pH= 5.70) and dark-cutting beef (pH = 6.60). Controls were made with no additives or with 1% salt and 10% added water. Various browning agents (1% glucose, 0.2% caramel colorant, 0.3% calcium peroxide, or 2.5% encapsulated lactic acid) were added with 10% water and 1% salt. Salt had a pronounced prooxidant effect on myoglobin. Distinctive absorption peaks at 541-548 nm and 577-582 nm indicated that the undenatured pigment in cooked patties was oxymyoglobin. Dark-cutting patties had more rubbery texture and slightly perceptible off-flavor. Patties with lactic acid were less juicy and had lower intensity of beef flavor than other patties, and moderate intensity of sour off-flavor. Addition of salt and encapsulated lactic acid to beef patty formulation could solve the problem of hard-to-cook patties.

Coacervation between the milk proteins β-lactoglobulin (BLG) and Lactoferrin (LF) was studied as a model system for hetero-protein coacervation (HPC). Equilibria among BLG/LF complexes and the corresponding speciation were found to control coacervation, which can be quantitatively monitored by turbidimetry. Several methods were used to assess complexation as a function of LF : BLG (mol/mol) mixing ratio (r). Proton release, calculated from a shift in pH when LF is added to BLG, was used to identify regions of complexation. Dynamic light scattering (DLS) was used to determine regions of complexation by relating complex size to stoichiometry. Isothermal titration calorimetry (ITC) was used to measure enthalpies of binding upon addition of LF to BLG. These results are used to show that coacervation is related to speciation, with the LF(BLG2)2 complex as the coacervating species.

Producing desirable firmness is important in manufacturing tofu from soybeans. This study’s objective was to explore the environmental impact (location and year) on soybean chemical components and identify the correlations between chemical composition and the firmness of tofu made from soybeans planted in three locations over two years. Seventeen soybean Plant Introductions (PI) from the USDA Soybean Germplasm Collection and eight check varieties were planted in Mississippi, Virginia and Missouri in 2017 and 2018. Protein subunit composition, protein secondary structure, phytic acid content, Ca2+ and Mg2+ content were determined. The result showed that A3 subunit content was strongly correlated with tofu firmness. Environmental factors had a significant influence on some chemical components in soybean seeds as well as tofu texture. The current study confirmed the validity of using A3 peptide as a criterion for estimating tofu firmness in both tofu manufacturing and food-grade soybean trade.

The umami sensation contributes to beef flavor and acceptability. Inosine 5’- monophosphate (IMP) was the most abundant nucleotide in meat known to impart umami taste which thus far had been overlooked in meat flavor studies. The objectives of this study were to determine the umami taste threshold of inosine 5'-monophosphate (IMP), the effects of spiking IMP on the sensory descriptive attributes of various USDA graded beef strip steaks, and to differentiate beef by IMP content using electrochemistry. USDA Prime, Choice, and Select steaks were spiked with 0.3 and 0.6 mM IMP and analyzed chemically and organoleptically. Liquid chromatography-mass spectrometry and descriptive sensory analysis showed no changes in IMP content and the perceived sensory attributes of steaks. The electrochemical approach successfully differentiated IMP concentrations in aqueous solutions when present at 0.5 mM or above and was able to recognize the presence of nucleotides in the meat extract.

<p>  </p> <p>  In this study, whey protein isolate (WPI) and high gellan gum (HAGG) were selected as natural ingredients to produce food-grade biopolymer particles for stabilizing the air-water interface. To achieve this, different mixing ratios of WPI and HAGG were employed, and heat treatment was implemented at different pH levels under the same concentration based on investigations of the pH-driven phase behavior of the WPI/HAGG complex system. The resulting WPI/HAGG complex particles were then evaluated for their ability to stabilize air-water interfaces by measuring their foaming properties.</p> <p><br></p> <p>  Foams generated using 0.1% (wt/wt) WPI/HAGG complex particles, heated at pH 5 with the mixing ratio 2:1 has demonstrated enhanced stability over a period of 30 hours compared to the WPI alone. The unique properties of these complex particles, including their smaller size (around 500nm), greater negative charge (more negative than -30 mV), and compact spherical core-shell structure, along with the higher viscosity in the continuous phase as well as the presence of small protein particles and gellan chains at the interface, collectively contribute to their superior performance as foam stabilizers. This allows for the creation of aerated food products with desirable characteristics, including product handling, enhanced texture, and prolonged shelf life in food industry.</p>