Alessandra Almeida Castro

Effects of nisin-incorporated films on the microbiological and physicochemical quality of minimally processed mangoes.

The aim of this study is to examine the effects of nisin-incorporated cellulose films on the physicochemical and microbiological qualities of minimally processed mangoes. The use of antimicrobial films did not affect the physicochemical characteristics of mangoes and showed antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, Alicyclobacillus acidoterrestris and Bacillus cereus. The mango slices were inoculated with S. aureus and L. monocytogenes (10(7)CFU/g), and the viable cell numbers remained at 10(5) and 10(6)CFU/g, respectively, after 12days. In samples packed with antimicrobial films, the viable number of L. monocytogenes cells was reduced below the detection level after 4days. After 6days, a reduction of six log units was observed for S. aureus. In conclusion, nisin showed antimicrobial activity in mangoes without interfering with the organoleptic characteristics of the fruit. This result suggests that nisin could potentially be used in active packing to improve the safety of minimally processed mangoes.

Estabilidade de ácido ascórbico, carotenoides e antocianinas de frutos de acerola congelados por métodos criogênicos

Quando se deseja manter a qualidade original do fruto, o congelamento pode ser o metodo selecionado, mas ocorrem mudancas fisicas e quimicas que sao prejudiciais a integridade estrutural do fruto, as quais sao menores quanto maior a velocidade de congelamento. O objetivo deste trabalho foi avaliar a estabilidade do acido ascorbico, das antocianinas e dos carotenoides totais de frutos de acerola congelados por metodo convencional (frio mecânico) a -22,1 °C e por metodos criogenicos, pela imersao em vapor de nitrogenio (N2(v)) a -180,9 °C e em nitrogenio liquido (N2(l)) a -196,2 °C, durante o armazenamento a -22,1 °C, por 60 dias. Os teores de acido ascorbico se mantiveram estaveis para todos os metodos de congelamento; no entanto, os criogenicos propiciaram maior retencao de carotenoides totais apos 60 dias, pois os frutos de acerola apresentaram reducoes de 7,64, 5,20 e 4,75%, para as amostras congeladas convencionalmente, por N2(v) e por N2(l), respectivamente. Ate o 60o dia, o metodo convencional propiciou a maior reducao (16,64%) no teor de antocianinas totais dos frutos. Essa maior degradacao das antocianinas dos frutos congelados pelo metodo mecânico pode ter sido favorecida por uma acao enzimatica, desencadeada pela formacao dos cristais de gelo grandes e pontiagudos, e ruptura das estruturas celulares. Em decorrencia da degradacao dos pigmentos, foram observados decrescimos dos parâmetros a* e b*, e aumento de L* das acerolas, para todos os metodos de congelamento, ao longo do armazenamento, sendo esses decrescimos maiores para as polpas dos frutos congelados convencionalmente. As amostras congeladas por criogenia apresentaram os menores valores de ΔE* em relacao ao padrao, ou seja, menor alteracao na cor ao longo do armazenamento. A aplicacao do congelamento criogenico antes do frio mecânico se mostrou vantajosa durante o armazenamento dos frutos de acerola, pois propiciou uma maior manutencao dos pigmentos responsaveis pela sua cor.

AVALIAÇÃO SENSORIAL, FÍSICO-QUÍMICA E MICROBIOLÓGICA DO LEITE FERMENTADO PROBIÓTICO DESNATADO ADICIONADO DE JENIPAPO DESIDRATADO OSMOTICAMENTE

There is a concern for people to consume more healthy foods, among these foods has been highlighted in recent years the probiotic fermented milk as well as having the nutritional characteristics of the basic food groups, also promotes beneficial health effects due to consumer action of probiotic bacteria existing in its constitution. As a consequence of these facts the present study aimed to develop and evaluate the probiotic fermented milk added with skim genipap osmotically dehydrated in relation to physicochemical, microbiological and sensory. We made the following physical and chemical analyzes (pH, titratable acidity, fat, protein, total solids, ash, carbohydrates and calories), microbiological (determining the number of lactic bacteria, most probable number (MPN) of coliforms at 35 and 45oC and counting total mesophile bacteria). In sensory analysis was applying the acceptance test for the following attributes: sweetness, aroma, texture, taste and overall impression and the determination of purchase intent. The results showed that fermented milk produced, kept during storage in the required microbiological standards ANVISA, the number of bacteria which is the microflora was 6.0 X10 7 CFU / mL after 28 days storage, the results of physicochemical and sensory show that the product has a high nutritional value and good acceptance by consumers, becoming a great alternative to commercial products since.