Ultrasonic pre-treatment to enhance drying of potentially probiotic guava (Psidium guajava): Impact on drying kinetics, Lacticaseibacillus rhamnosus GG viability, and functional quality.

This study aimed to evaluate the effects of ultrasound (US) on the drying acceleration of potentially probiotic guava, including its impact on drying kinetics, probiotic (Lacticaseibacillus rhamnosus GG) viability, and functional quality of the product during drying. To perform US pre-treatments, one group of samples were first pre-treated by US (38 W/L, 25 kHz) for 15 and 30 min and then immersed in the probiotic solution for 15 or 30 min, and another group of samples were submerged in the probiotic solution simultaneously applying US (US-assisted) for 15 and 30 min. After pre-treatments, the samples were convectively dried at 60 °C. Based on the results, all US pre-treatments improved the drying rate (up to 59%) and reduced the drying time (up to 31%) to reach 25% moisture compared to non-sonicated samples. The reduction in drying time (from ∼6 h to ∼4 h for US pre-treated samples) was crucial for maintaining the probiotic viability in the dehydrated guavas. These samples showed counts of 6.15 to 7.00 CFU∙g-1 after 4 h, while the control samples reached counts of 4.17 to 4.45 CFU∙g-1 after 6 h. US pre-treatment did not affect the color parameters of the samples before drying (p > 0.05). The functional compounds were reduced during drying (p < 0.05), however, all US pre-treated samples had lower reductions in vitamin C content (up to 20%), phenolic compounds (up to 41%) and antioxidant capacity (up to 47%) compared to control samples (up to 52%, 81% and 61%, respectively). Therefore, US pre-treatment (highlighting the US-assisted probiotic incorporation for 30 min) reduced the drying time for guava slices and minimized the thermal impact on probiotic viability and functional compounds, being a strategy to produce potentially probiotic dehydrated guava.

Impact of ultrasound and protease addition on the fermentation profile and final characteristics of fermented goat and sheep cheese whey.

Goat (GCW) and sheep cheese whey (SCW) are cheese by-products that can be fermented to develop a new product. However, the limited nutrient availability for lactic acid bacteria (LAB) growth and the low stability of whey are challenges. This work evaluated the addition of protease and/or ultrasound-assisted fermentation as tools to improve GCW and SCW fermentation and the final quality of the products. Results showed that the US/protease increased by 23-32% pH decline rate (for SCW only) and modified the separation of cream (≤ 60% for GCW) and whey (≤ 80% for both whey sources, with higher values for GCW) during storage, explained by changes in the microstructure protein, fat globules, and their interactions. Furthermore, the whey source/composition (mainly lower fat content in SCW) affected the destabilization rate and the LAB viability loss (1.5-3.0 log CFU/mL), caused by nutrient depletion and low tolerance at pH ~ 4.0. Finally, exploratory results showed that fermentation under sonication (with/without protease) resulted in 24-218% higher antioxidant activity in vitro than unfermented samples. Therefore, fermentation associated with proteases/sonication can be an interesting strategy to modify GWC and SCW, and the final process chosen depends on the desired changes in whey. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05767-3.

Use of maltodextrin, sweet potato flour, pectin and gelatin as wall material for microencapsulating Lactiplantibacillus plantarum by spray drying: Thermal resistance, in vitro release behavior, storage stability and physicochemical properties.

Different plant products and co-products have been studied as wall materials for the microencapsulation of probiotics due to the need for new lost-cost, abundant, and natural materials. In this study, microparticles were developed by spray drying using different combinations of conventional materials such as maltodextrin, pectin, gelatin, and agar-agar with unconventional materials such as sweet potato flour to microencapsulate Lactiplantibacillus plantarum. The microparticles obtained were evaluated for encapsulation efficiency, thermal resistance, and rupture test. The most resistant microparticles were characterized and evaluated for probiotic viability during storage and survival to in vitro gastrointestinal conditions. Microparticles A (10 % maltodextrin, 5 % sweet potato flour, and 1 % pectin) and B (10 % maltodextrin, 4 % sweet potato flour, and 2 % gelatin) showed high thermal resistance (>59 %) and survival in acidic conditions (>80 %). L. plantarum in microparticles A and B remained viable with counts > 6 log CFU.g-1 for 45 days at 8 °C and -18 °C and resisted in vitro gastrointestinal conditions after processing with counts of 8.38 and 9.10 log CFU.g-1, respectively. Therefore, the selected microparticles have great potential for application in different products in the food industry, as they promote the protection and distribution of probiotic microorganisms.

Ultrasound-assisted enzymatic hydrolysis of goat milk casein: Effects on hydrolysis kinetics and on the solubility and antioxidant activity of hydrolysates.

This study evaluated the ability of ultrasound (US) bath to improve the hydrolysis of goat milk casein (GMC) by three commercial proteases (Alcalase, Brauzyn and Flavourzyme) using assisted reactions at 60 °C for up to 300 min. Process performance was evaluated based on the rate reaction, final hydrolysis degree, solubility, and antioxidant activity of the hydrolysates. For all enzymes, the US-assisted reaction increased the rate of GMC hydrolysis (up to 120%), the hydrolysis degree (23-48%), and the small peptides formed, i.e., those soluble in trichloroacetic acid (TCA) (up to 40%). Consequently, US-assisted GMC hydrolysis improved the solubility of the hydrolyzed product (up to a 35.7% increase after 300 min of reaction) and, compared to conventional hydrolysis, reduced the time to achieve the maximum solubility by up to 10 times. Regarding the in vitro antioxidant activity, especially for Alcalase, the technology promoted a higher scavenging capacity of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (p < 0.05), thus 10-fold accelerating the production of antioxidant peptides, according to ABTS assays (p < 0.05). In conclusion, the US-assisted enzymatic reaction is a promising technology to improve the hydrolysis rate and yield of the process of obtaining hydrolysates from GMC. Moreover, these hydrolysates showed high solubility and good in vitro antioxidant activity, which demonstrates the potential to be used as food ingredient with nutritional and techno-functional appeal.

Use of physical processes to maximize goat milk cream hydrolysis: Impact on structure and enzymatic hydrolysis.

This study evaluated the use of ultrasound (US), high-shear dispersion (HSD), stirring (ST), and low or high pressure homogenization (LPH or HPH) technologies to modify the goat milk cream (GMC) structure, focusing on improving the enzymatic hydrolysis of its lipids. The GMC structure was evaluated, as well as its creaming and emulsion stability index (ESI). The processed GMC was hydrolyzed by lipase at 50 °C for 300 min, and the fatty acids concentration (FAC) was evaluated over the reaction. ST, HPH, and HSD showed âˆ¼ 90% lower emulsion destabilization, 10 times higher ESI, and smaller fat globule size than unprocessed GMC. The pretreatments increased the hydrolysis rate up to 2.4 times and the final FAC up to 8.7 times. ST (4 min), HPH (40 MPa) and HSD (5 min/ 25,000 rpm) showed the best results, which were correlated with the changes in the GMC structure. The results suggest that the physical treatments impacted the substrate structure, favoring enzyme activity and accelerating the hydrolysis degree. Therefore, the application of physical processes can be an interesting strategy to enhance the hydrolysis of GMC, aiming to produce compounds of industrial interest.

Mango and carrot mixed juice: a new matrix for the vehicle of probiotic lactobacilli.

This study evaluated the pH, acidity, soluble solids, color, dietary fiber, sensory acceptance and the viability of Lactobacillus rhamnosus, Lactobacillus plantarum and Lactobacillus acidophilus in mango and carrot mixed juices. In addition, this study verified the resistance of L. plantarum that presented greater viability to the gastrointestinal tract simulated in vitro. Three formulations were elaborated (varying the pulps concentration) and the products were stored at 8 °C for 35 days. No difference was found in the total soluble solids and color of the products during storage time at 8 °C. A reduction in pH and an increase in acidity were observed in all samples during storage, probably due to the fermentative action of probiotics, which negatively influenced acceptance after 35 days of storage. On the other hand, juices with a higher concentration of mango pulp were more accepted and may be a strategy to improve the acceptance of fermented juices. Microorganisms showed greater viability in juices that had higher amount of carrot pulp, probably due to the higher fiber content in these samples. During the 35-day shelf life, all juices with L. plantarum maintained counts above 7 log CFU mL-1 after gastrointestinal conditions simulation. Therefore, mango and carrot mixed juice showed to be as a good vehicle for probiotic bacteria and meets the needs of consumers looking for functional, healthy, non-dairy and low-sugar foods.

Avaliação sensorial e microbiológica de bebida mista de vegetais adicionada de probiótico / Sensory and microbiological evaluation of mixed vegetable drinks with probiotic

Bebidas de origem vegetal vêm sendo estudadas como carreadoras de bactérias probióticas. Neste estudo objetivou-se elaborar duas bebidas mistas probióticas sabor goiaba e beterraba: BMAP (bebida mista à base de extrato de amendoim) e BMSP (à base de extrato de soja), que foram adicionadas de Lactobacillus rhamnosus GG. Avaliaram-se características sensoriais e microbiológicas das bebidas elaboradas e de uma bebida comercial a base de soja disponível no mercado (BSC). Verificou-se que, após o processamento, as bebidas BMAP, BMSP e a BSC apresentaram escores equivalentes a "gostei ligeiramente" e "gostei muito" para os atributos acidez, cor, sabor, aroma, textura e impressão global, e escores equivalentes a "talvez comprasse, talvez não comprasse" e "provavelmente compraria" na avaliação de intenção de compra, não havendo diferença das bebidas elaboradas para a comercial. Verificaram-se contagens de LGG superiores a 6,8 Log UFC. mL-1 nas bebidas. Todas as amostras estavam de acordo com os padrões microbiológicos exigidos pela legislação brasileira. As bebidas apresentam potencial de mercado e são consideradas um excelente veículo de LGG, além de uma nova opção de bebida funcional, não láctea, acessível à população.(AU)

Vegetable beverages have been studied as carriers of probiotic bacteria. The objective of this study was to elaborate two probiotic mixed beverages from guava and beet: BMAP (mixed beverage based on peanut extract) and BMSP (based on soy extract), which were added of Lactobacillus rhamnosus GG. Beverages from both matrices, without addition of probiotic, were denominated control (BMAC and BMSC). Sensory and microbiological characteristics of the elaborated beverages and a commercially available commercial soybean drink (BSC) were evaluated. It was verified that, after the processing, the BMAP, BMSP and BSC beverages presented "slightly liked" and "liked" scores for the attributes of acidity, color, flavor, aroma, texture and overall impression, and " maybe buy, maybe not buy "and" would probably buy "in the evaluation of the intention to buy, there being no difference of the beverages from to the commercial. LGG counts were above 6.8 Log UFC.mL-1 in the beverages. All samples were in accordance with the microbiological standards required by Brazilian legislation. The beverages present market potential and are considered a excellent vehicle of LGG and a new functional beverage option, not dairy, accessible to the population.

Effect of dynamic high pressure on functional and structural properties of bovine serum albumin.

Dynamic high pressure (DHP) has been investigated as an innovative suitable method to induce protein modifications. This work evaluated the effect of DHP (up to three passes at 100, 150 and 200MPa, with an inlet temperature of 20°C) on functional and structural properties of bovine serum albumin (BSA). Results indicated that DHP process applied up to an energy limit of 100MPa increased the protein foaming capacity (FC) (p<0.05 - increase up to 63% after 1 pass at 100MPa) and the utilization of multiple passes at high pressure promoted a reduction in this property (p<0.05 - reduction up to 31.6% after 3 passes at 200MPa). Similar results were observed for sulfhydryl group, indicating an influence of free thiol groups on FC. Complementarily, DHP process promoted an increase of proteins particles size, suggesting a new rearrangement of their conformational structure. DHP did not affect tryptophan microenvironment in BSA; however, this process induced the rearrangement of secondary structure elements. In the first cycle, the pressure increase resulted in a loss of secondary structure, while in the second and third cycles the DHP process resulted in the gain of secondary structure elements. These results indicated that the second and third passes triggered a molecular rearrangement of the protein structure, giving rise to a novel and more stable conformational state. This conclusion was also supported by thermal unfolding studies (melting temperature reduction from 67.5 to 54.6°C after 1 pass at 200MPa), in which the additional cycles of DHP caused the occurrence of an initial denaturation at high temperatures, compared to the first cycle.

Biophysical evaluation of milk-clotting enzymes processed by high pressure.

High pressure processing (HPP) is able to promote changes in enzymes structure. This study evaluated the effect of HP on the structural changes in milk-clotting enzymes processed under activation conditions for recombinant camel chymosin (212MPa/5min/10°C), calf rennet (280MPa/20min/25°C), bovine rennet (222MPa/5min/23°C), and porcine pepsin (50MPa/5min/20°C) and under inactivation conditions for all enzymes (600MPa/10min/25°C) including the protease from Rhizomucor miehei. In general, it was found that the HPP at activation conditions was able to increase the intrinsic fluorescence of samples with high pepsin concentration (porcine pepsin and bovine rennet), increase significantly the surface hydrophobicity and induce changes in secondary structure of all enzymes. Under inactivation conditions, increases in surface hydrophobicity and a reduction of intrinsic fluorescence were observed, suggesting a higher exposure of hydrophobic sites followed by water quenching of Trp residues. Moreover, changes in secondary structure were observed (with minor changes seen in Rhizomucor miehei protease). In conclusion, HPP was able to unfold milk-clotting enzymes even under activation conditions, and the porcine pepsin and bovine rennet were more sensitive to HPP.

Vida de prateleira de alface americana tratada com água ozonizada / Shelf life evaluation of the iceberg lettuce sanitized with ozone water

RESUMO:Este trabalho avaliou se a higienização de alface americana com água ozonizada, na concentração de 1,0mg L-1 por 1, 2 ou 3 minutos, seria capaz de aumentar a vida útil do produto quando armazenado a 2ºC. Foram avaliadas as populações de microrganismos aeróbios mesófilos, Enterobacteriaceae, bolores e leveduras, coliformes totais, coliformes termotolerantes e pesquisa de Salmonellasp ao longo do tempo. Imediatamente após o processamento por 3 minutos, foram obtidas reduções decimais de 4,07; 3,36; 3,20; 2,18 e 2,18 de microrganismos aeróbios mesófilos,Enterobacteriaceae, bolores e leveduras, coliformes totais, coliformes termotolerantes, respectivamente. A presença de Salmonellasp. não foi observada em nenhuma das condições estudadas. Além do efeito na inativação inicial, o processamento com ozônio melhorou a estabilidade da alface durante a estocagem, aumentando o tempo para o início do crescimento microbiano (de zero para quatro dias) e reduzindo a taxa de crescimento dos microrganismos, especialmente quando a sanitização foi realizada por 3 minutos de contato. Os resultados demonstraram que a alface tratada com água ozonizada atendeu aos parâmetros da legislação durante o período avaliado, reduzindo a contaminação inicial das alfaces (que, sem tratamento, estavam microbiologicamente impróprias para consumo pela contagem de coliformes) e mantendo essas contaminações em níveis aceitáveis por até 10 dias, sob refrigeração.

ABSTRACT:This research studied the impact of Iceberg lettuce sanitation using ozonized water at 1.0mg L-1 for 1, 2 and 3 minutes in the vegetable shelf-life at 2ºC. It was evaluated populations of aerobic mesophilic bacteria, EnterobacterIaceae, molds/yeasts, total and thermtolerants coliforms, andSalmonellasp. Immediately after 3 minutes of sanitation, decimal reductions of 4.07 (aerobic mesophilic bacteria), 3.36 (EnterobacterIacea), 3.2 (molds/yeasts), 2.18 (total coliforms) and 2.18 (thermtolerants coliforms) were reached. Salmonellasp. was not founded at any evaluated condition. Additionally to the initial reduction, the ozonization improved the lettuce stability during its shelf-life, increasing the delay for microbial growth (from zero to four days) and reducing the microbial growth rate. It occurred especially when sanitation with ozone was carried for 3 minutes of contact. The results showed that the Iceberg lettuce sanitized with ozonated water meets the Brazilian law during the evaluated period, reducing lettuce initial load (that was initially unsafe due to high count of coliforms) and keeping this contamination acceptable for 10 days under refrigeration.

High Pressure Homogenization of Porcine Pepsin Protease: Effects on Enzyme Activity, Stability, Milk Coagulation Profile and Gel Development.

This study investigated the effect of high pressure homogenization (HPH) (up to 190 MPa) on porcine pepsin (proteolytic and milk-clotting activities), and the consequences of using the processed enzyme in milk coagulation and gel formation (rheological profile, proteolysis, syneresis, and microstructure). Although the proteolytic activity (PA) was not altered immediately after the HPH process, it reduced during enzyme storage, with a 5% decrease after 60 days of storage for samples obtained with the enzyme processed at 50, 100 and 150 MPa. HPH increased the milk-clotting activity (MCA) of the enzyme processed at 150 MPa, being 15% higher than the MCA of non-processed samples after 60 days of storage. The enzyme processed at 150 MPa produced faster aggregation and a more consistent milk gel (G' value 92% higher after 90 minutes) when compared with the non-processed enzyme. In addition, the gels produced with the enzyme processed at 150 MPa showed greater syneresis after 40 minutes of coagulation (forming a more compact protein network) and lower porosity (evidenced by confocal microscopy). These effects on the milk gel can be associated with the increment in MCA and reduction in PA caused by the effects of HPH on pepsin during storage. According to the results, HPH stands out as a process capable of changing the proteolytic characteristics of porcine pepsin, with improvements on the milk coagulation step and gel characteristics. Therefore, the porcine pepsin submitted to HPH process can be a suitable alternative for the production of cheese.