RESUMO
The production of value-added and/or functional juices has increased significantly in recent years, following an increased consumer demand to promote health and/or prevent disease through diet and nutrition. Micro and nano-encapsulation are promising technologies to protect and deliver sensitive compounds, allowing a controlled release in the target sites. This paper offers an overview of current applications, limits and challenges of encapsulation technologies in the production of fruit and vegetable juices, with a particular emphasis on products derived from different botanical sources.
Assuntos
Sucos de Frutas e Vegetais/análise , Aromatizantes , Manipulação de Alimentos , Nanotecnologia , ProbióticosRESUMO
This paper proposes the microencapsulation into alginate beads of 4 isolates of lactic acid bacteria (Lactobacillus spp.), previously isolated from pork meat. First, the beads were studied in relation to the encapsulation yield (EY), kinetic of cell release in a structured system, and survival throughout bead storage at 4 °C. EY was 93-96% and the survival of the encapsulated microorganisms was variable, with two isolates showing a bacterial population of 6.1-6.9 log cfu/g after 35 days under refrigerated conditions. Thereafter, the paper addressed a preliminary validation in a meat model system, containing salt, nitrites and nitrates, lactose, pepper, and then in a commercial preparation of pork meat. For the validation in pork meat, free cells were used as controls. Cell released from beads were able to achieve a significant acidification; in particular, after 7 days they showed the same results of free cells.
Assuntos
Alginatos/química , Aditivos Alimentares/química , Lactobacillus plantarum/crescimento & desenvolvimento , Produtos da Carne/microbiologia , Modelos Biológicos , Animais , Células Imobilizadas , Fermentação , Armazenamento de Alimentos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Concentração de Íons de Hidrogênio , Itália , Cinética , Lactobacillus plantarum/isolamento & purificação , Lactobacillus plantarum/metabolismo , Produtos da Carne/análise , Viabilidade Microbiana , Microesferas , Probióticos/isolamento & purificação , Probióticos/metabolismo , Refrigeração , Sus scrofaRESUMO
Enterobacter cloacae can be recovered in the spontaneous fermentations of Italian table olives. In this study, the effects of salt (20 to 100 g/L), temperature (10 to 37 degrees C), pH (4 to 5 and 8 to 10), p-coumaric and vanillic acids (0.5 to 2 g/L), and the acidification of the medium through lactic, citric, and ascorbic acids were investigated on 15 strains of E. cloacae, isolated from Italian table olives "Bella di Cerignola." Finally, a confirmatory experiment in synthetic brine was run. The strains were inhibited only by an NaCl amount of 70 to 80 g/L and by p-coumaric acid; on the other hand, they showed the ability to grow also at low temperatures (10 to 15 degrees C). The confirmatory experiment highlighted their ability to survive both at 15 degrees C and at pH 5. Enterobacter cloacae could be a real problem for the fermentation of table olives in southern Italy; some hurdles could be used (salt or brine acidification), but some environmental conditions (for example, the temperature) should be controlled carefully to maintain olive safety at acceptable levels.