Effect of extrusion process conditions on extrudates enriched with carotenoids encapsulated by different methods using gum arabic and vegetable fat as carriers.

Bioactive compounds into extruded foods enhance their nutritional value but they are heat and shear labile and prone to oxidation. This study was aimed to examine the impacts of distinct encapsulation methods on the stability of carotenoids under typical extrusion conditions. The study presents innovative encapsulation methods and investigates the protection efficacy of carotenoids degradation, as well as the effects on the physicochemical characteristics of carotenoid-rich products. Thus, spray drying, spray chilling, and their combination were compared based on their ability to protect carotenoids. Processing temperatures were 110 °C and 140 °C, and shear rates 500 and 2000 1/s. Carotenoid retention was determined, ß- and α-carotene retention ranged from 17 to 44 % and 18 to 48 %, respectively. Upon storage at room temperature, the carotenoid content was stable for 15 days, followed by a marked reduction after 30 days. Extrudates enriched microparticles produced by spray chilling and the combined methods exhibited higher carotenoid protection during storage. They also showed better quality attributes, notably bulk density, high water absorption index, color properties, and carotenoid retention. These findings suggest that encapsulation can protect carotenoids during extrusion, and the protection can be tailored to optimize the attributes of the final products.

Grape Pomace Rich-Phenolics and Anthocyanins Extract: Production by Pressurized Liquid Extraction in Intermittent Process and Encapsulation by Spray-Drying.

A considerable number of grape pomaces are generated annually. It represents a rich source of bioactive compounds, such as phenolic compounds and anthocyanins. Pressurized liquid extraction (PLE) has emerged as a green technology for recovering bioactive compounds from vegetal matrixes. In our study, PLE parameters (temperature, number of cycles, and rinse volume) have been studied to produce grape pomace extracts with high bioactive content using an experimental design. The experimental data obtained were adjusted to linear and quadratic models. The first-order model was better in predicting anthocyanins contents (TA, R2 = 0.94), whereas the second-order model was predictive for total phenolic compounds (TPC, R2 = 0.96). The main process parameter for the recovery of bioactive compounds was temperature, and the results showed opposing behaviors concerning TPC and TA, as it is difficult to optimize conditions for both. The extract containing the higher concentration of TPC (97.4 ± 1.1 mg GAE/g, d.b.) was encapsulated by spray-drying using maltodextrin as wall material. Particles presented with a spherical shape (~7.73 ± 0.95 µm) with a recovery yield of 79%. The results demonstrated that extraction followed by encapsulation of grape pomace extract is a good strategy to simplify future applications, whether for food, cosmetics or pharmaceutical fields.

Study of the Oxidative and Microbiological Stability of Nitrite-Reduced, Vacuum-Packed, Refrigerated Lamb Sausages Supplemented with Red Propolis Extract.

Vacuum-packed lamb sausages with or without red propolis extract and a reduced sodium nitrite content were evaluated for oxidative and microbiological stability during storage for 21 days at 2 °C. The following treatments were evaluated: EN150 (control, base formulation (BF) + 500 mg/kg sodium erythorbate and 150 mg/kg sodium nitrite); EN75 (BF + 500 mg/kg sodium erythorbate and 75 mg/kg sodium nitrite); P1N75 (without the addition of erythorbate, BF + 1800 mg/kg propolis extract and 75 mg/kg sodium nitrite); and P2N75 (without the addition of erythorbate, BF + 3600 mg/kg propolis extract and 75 mg/kg sodium nitrite). Analyses were conducted to characterize the samples on day 0 with respect to the proximate composition (moisture, protein, fat, and ash) and sensory acceptance. Stability during refrigerated storage was evaluated on days 0, 7, 14 and 21 for the parameters pH, color profile (L*, a*, and b*), TBARs index (oxidative stability) and microbiological count of aerobic psychrotrophic microorganisms. Texture profile, cooking weight loss (WLC), peroxide index and free fatty acids were evaluated on days 0 and 21. The treatments with propolis and reduced nitrite (EN150 and P1N75) showed a red color intensity (a*) similar to the treatment with erythorbate and the same nitrite content (EN75) at the end of storage, maintaining the characteristic reddish color of the sausages. The extract slowed down lipid oxidation during storage, especially P2N75, which showed the lowest level of TBARS (0.39 mg MDA/kg) and the peroxide index (2.13 mEq g O2) on day 21. The residual nitrite value in EN75 was the lowest (p < 0.05) on day 21, showing that synthetic antioxidants are more efficient than the extract in nitrite reduction reactions. The results for the counts of psychrotrophic microorganisms showed that the extract did not have the expected antimicrobial effect on the growth of this microorganisms, and leveling the results revealed no differences (p < 0.05) between the treatments. Despite the red propolis extract not showing a significant antimicrobial improvement in lamb sausages, it can be considered a healthy option with good prospects for replacing synthetic antioxidants with a natural product.

Stability of free and immobilized Lactobacillus acidophilus and Bifidobacterium lactis in acidified milk and of immobilized B. lactis in yoghurt

Este trabalho avaliou a estabilidade de Bifidobacterium lactis (Bb-12) e de Lactobacillus acidophilus (La-05) nas formas livre e imobilizada em alginato de cálcio, em leite e leite acidificado (pHs 5.0, 4.4 e 3.8), e a estabilidade de B. lactis imobilizado em iogurte (fermentado até pH 4.2), durante 28 dias de estocagem refrigerada. Também foi estudada a eficiência de dois meios de cultura (ágar MRS modificado e Reinforced Clostridial Agar, acrescido de Prussian Blue) para enumerar B. lactis em iogurte. Agar Lee foi usado para enumeração de Streptococcus thermophilus e Lactobacillus delbrueckii ssp. bulgaricus quando B. lactis era enumerado no meio MRS. Ambos os microrganismos, nas formas livre e imobilizada, apresentaram uma taxa de sobrevivência adequada nos leites acidificados, uma vez que houve redução de apenas um ciclo log, após 21 dias de estocagem refrigerada. O número de células viáveis de B. lactis imobilizado mostrou um declínio gradual durante o período de armazenamento do iogurte, passando de 108 ufc/ml até não ter mais contagem na diluição 10-1. Quando as culturas não estavam em equilíbrio, o meio MRS modificado foi mais eficiente para a contagem de B. lactis em iogurte. Em vista destes resultados pode-se concluir que ambos os microrganismos podem ser incorporados em leite e leite acidificados, haja visto que a redução na população foi pequena durante o período de armazenagem estudado. A presença da cultura tradicional de iogurte parece ter afetado negativamente a sobrevivência de B. lactis e a imobilização não proveu proteção às células, em nenhum dos tratamentos estudados.