Biopreservation of Fior di Latte cheese

Abstract In this study a new biopreservation system consisting of an active sodium alginate coating containing Lactobacillus reuteri applied to Fior di Latte cheese was studied. The final aim was to extend cheese shelf life by the in situ production of reuterin. Experimental trials were carried out with and without glycerol. How the fermentation time could improve the production of reuterin, enabling Fior di Latte shelf life, was also assessed. To this aim, the experimental analyses were conducted in 2 different trials, using 2 different production batches of samples. In the first one, Fior di Latte samples were dipped into the active sodium alginate solution prepared on the same day of their production, whereas in the second trial, samples were dipped into the active solution prepared 48h before their production to allow a proper fermentation of the inoculated microorganism. Microbiological and sensory quality indices were monitored to prove the effectiveness of biopreservation on product quality during storage. In the first trial, the combination of the probiotic microorganism with glycerol improved the microbial quality by 1 d compared with the same active solution without glycerol, whereas the 48-h-fermented active alginate solution (second trial) showed a further improved microbial quality. The application of an active coating enriched with L. reuteri and glycerol to Fior di Latte cheese is an optimal and innovative way to preserve the product and at the same time, with a combination of an optimal fermentation time, to prolong its microbial quality and thus its shelf life

Revestimento ativo de amido na conservação pós-colheita de pera Williams minimamente processada Starch-based edible coating on extending shelf life of fresh-cut pear

A pera é uma das frutas de clima temperado mais consumidas no Brasil, no entanto sua conservação é limitada devido ao seu escurecimento quando sofre danos ou tratamentos físicos. Os revestimentos comestíveis interagem favoravelmente com o alimento, aumentando sua vida de prateleira. Este trabalho objetivou avaliar a ação de revestimento de amido adicionado de lactato de cálcio e L-cisteína na inibição do escurecimento enzimático, na redução do crescimento de psicrotrófilos e enterobactérias e na manutenção da textura. As peras fatiadas foram cobertas com revestimentos comestíveis à base de amido incorporados com cisteína e lactato de cálcio, exceto o controle - sem revestimento (C). Os tratamentos foram: apenas revestimento (T1); 2,0% lactato de cálcio e 1,0% L-cisteína (T2) e 2,0% lactato de cálcio e 1,5% L-cisteína (T3). As amostragens foram feitas nos tempos zero, dois, quatro e seis dias. As amostras foram mantidas sob refrigeração (7&deg;C&plusmn;2&deg;C). As peras submetidas aos tratamentos T2 e T3 apresentaram-se significativamente mais firmes (P<0,05) que as dos tratamentos C e T1. A ação da cisteína sobre a inibição do escurecimento enzimático foi observada nos tratamentos T2 e T3, que não apresentaram diferença significativa (P&#8805;0,05) entre si para os valores de &#8710;E, no entanto esses valores foram significativamente menores em relação ao controle. No tempo 6, a redução decimal na contagem de psicrotrófilos chegou a 3,03 e 2,43 para T3 e T2, em comparação com o controle. A contagem de enterobactérias apresentou comportamento semelhante, sendo o valor da redução de 3,16 e 3,05 para T2 e T3 em relação ao controle. Verificou-se que a vida de prateleira de pera minimamente processada pode ser mantida por mais tempo com o uso desse revestimento.<br>Pear is one of the most consumed temperate fruits in Brazil; however their conservation is limited due to browning when it suffers injuries or physical treatments. The edibles coating interact with the food positively extending its shelf life. This research aimed to evaluate the action of starch edible coating incorporated with calcium lactate and L-cysteine on enzymatic browning inhibition, on psychrotrophs and enterobacteriaceae growing reduction and on firmness maintenance. The sliced pears were coated with starch edible coating incorporated with L-cysteine and calcium lactate, except control, without coating (C). The treatment were: only coating (T1); 2,0% calcium lactate and 1,0% L-cysteine (T2); 2,0% calcium lactate and 1,5% L-cysteine (T3). The samples were taken at 0, 2, 4 and 6 days. Pears were keeped under refrigeration (7&deg;C&plusmn;2&deg;C). Pears submitted to treatments T2 and T3 show significantly more firms (P<0,05) compared to treatments C and T1. Cysteine action over enzymatic browning inhibition was observed in treatments T2 and T3 which do not differed significantly each other (P&#8805;0,05) to &#8710;E values however these were significantly lower than control (C). At time 6, decimal reduction on psychrotrophs counting reached 3,03 and 2,43 to T3 e T2 compared to control. Enterobacteriaceae counting showed similar behavior where the reduction values were 3,16 and 3,05 to T2 e T3 compared to control. It was verified that using the studied edible coating on fresh cut pear can extend its shelf life