Evaluation of the release, stability and antioxidant activity of Brazilian red propolis extract encapsulated by spray-drying, spray-chilling and using the combination of both techniques.

Red propolis, originary from Northeast Brazil, has a unique composition and a great commercial interest. However, due to the presence of ethanol and its remarkable sensory characteristic, its application in food products is challenging. Thus, the aim of this work was to microencapsulate the red propolis extract by spray-drying, spray-chilling, and combining both techniques. The particles loaded with propolis extracts were characterised and evaluated according to the stability of phenolic compounds, flavonoids and formononetin, during 60 days of storage. In addition, the formononetin release was also monitored during the oral, gastric, and intestinal phases in the in vitro digestion process. All produced particles presented matrix-type with size, distribution, shape, hygroscopicity, and dispersibility parameters that varied according to the carrier and encapsulation process applied. The techniques used to fabricate the particles efficiently obtained powdered propolis extract and protected the extract's bioactive compounds, total flavonoids and formononetin throughout the analysed period. The gastrointestinal release study presented distinctive releases in all phases (oral, gastric, and intestinal). The spray-dried particles, for example, released formononetin mainly in the oral stage. While the spray-chilled particles were primarily released in the intestinal phase, and coated particles were released gradually throughout the assay, reaching maximum relief in the intestinal phase. In conclusion, using microencapsulation techniques by spray-drying, spray-chilling, and their combination developed particles with different levels of protection during storage, releases and characteristics, which resulted in a range of possible applications in the food, feed, cosmetic, and pharmaceutical industries.

Changes in food caused by deep fat frying - A review

Deep-fat frying is widely used in food industries because of its low cost and high demand, since it produces convenient food of high acceptability. The process is based on the oil-food interaction at high temperatures, which cooks and dehydrates the food, leading to physical and chemical changes, such as starch gelatinization, protein denaturation, flavoring and color production via Maillard reaction. Some food and oil compounds are lost in the frying process, and potentially toxic compounds are developed in the oxidized oil. Although widely studied, many of these compounds have not been fully identified. The purpose of this study was to review literature findings on changes in food caused by the frying process.

Alterações nos alimentos causados pelo processo de fritura- Revisão. O processo de fritura é amplamente utilizado em indústria de alimentos devido ao baixo custo e alta demanda pela praticidade e grande aceitação. O processo é baseado na interação óleo-alimento a altas temperaturas, que cozinha o alimento e desidrata, levando a alterações físicas e químicas assim como a gelatinização do amido, desnaturação de proteínas, aroma e produção de cor através da reação de Maillard. Alguns compostos presentes nos alimentos e no óleo são perdidos no processo de fritura, e componentes potencialmente tóxicos são desenvolvidos nos óleos oxidados. Embora diversos tenha havido avanços na identificação desses componentes, muitos ainda não foram identificados. A proposta desse trabalho foi avaliar as alterações nos alimentos causadas pelo processo de fritura.

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

This study evaluated the stability of Bifidobacterium lactis (Bb-12) and of Lactobacillus acidophilus (La-05) both free and immobilized in calcium alginate, in milk and in acidified milk (pH 5.0, 4.4 and 3.8). The stability of immobilized B. lactis in yoghurt (fermented to pH 4.2), during 28 days of refrigerated storage was also evaluated. The efficiency of two culture media (modified MRS agar and Reinforced Clostridial Agar plus Prussian Blue) for counting of B. lactis in yoghurt was determined. Lee's agar was used to count Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus when B. lactis were counted in the MRS medium. B. lactis and L. acidophilus in both free and immobilized forms presented satisfactory rates of survival in milk and acidified milk because the average reduction of the population was only one log cycle after 21 days of storage. The number of viable cells of immobilized B. lactis in yoghurt presented a gradual decline throughout the storage period, passing from 10(8) cfu/ml to no count after 28 days of storage. When the cultures were not in equilibrium just the selective medium was efficient in counting B. lactis in yoghurt. The results showed that both microorganisms can be added to milk and acidified milk, because their population was only slightly affected during storage. The presence of traditional culture of yoghurt seems to be harmful for survival of immobilized B. lactis and the immobilization in calcium alginate failed as an effective barrier to protect the cells in all analysed treatments.

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. Ágar 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 10(8) 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.