RESUMO
The aim of this work was to evaluate the impact of two factors on the ripening profiles of hard cooked cheeses: (F1) the growth medium for the primary and adjunct cultures, constituted by autochthonous strains: Lactobacillus helveticus 209 (Lh209) and Lactobacillus paracasei 90 (Lp90), respectively, and (F2) the addition of L. paracasei Lp90 as adjunct culture. Four types of cheeses were made: W and M cheeses in which only Lh209 was added after its growth in whey and MRS, respectively; Wa and Ma cheeses in which both strains (Lh209 and Lp90) were added after their growth in whey and MRS, respectively. Physicochemical and microbial composition, proteolysis and profiles of organic acids and volatile compounds were analyzed. According to the methodology of the cultures preparation, W and Wa cheeses showed a higher level of secondary proteolysis and lower level of primary proteolysis (P < 0·05), lower content of citric and acetic acids and higher amount of propionic acid (P < 0·05), in comparison with M and Ma cheeses. The incorporation of Lp90 increased the secondary proteolysis (P < 0·05), decreased the citric acid (P < 0·05), and increased the propionic acid only when was added after their growth in whey (P < 0·05). Both factors significantly modified the percentages of the volatile compounds grouped in chemical families; in addition, for the half of the compounds detected, significant differences were found. Based on the obtained results, the use of Lp90 as an adjunct in hard cooked cheeses, and the preincubation of the cultures in whey are strategies to accelerate the cheese ripening and to enhance the production of some characteristic compounds of this type of cheeses, such as propan-2-one, hexan-2-one, 2- and 3-methyl butanal, heptan-2-ol, acetic and 3-methylbutanoic acids and 3-hydroxy butan-2-one.
Assuntos
Queijo/análise , Queijo/microbiologia , Tecnologia de Alimentos/métodos , Lacticaseibacillus paracasei/crescimento & desenvolvimento , Lactobacillus helveticus/crescimento & desenvolvimento , Ácido Acético/análise , Carboidratos/análise , Fenômenos Químicos , Ácido Cítrico/análise , Meios de Cultura , Fermentação , Manipulação de Alimentos/métodos , Concentração de Íons de Hidrogênio , Lactobacillus helveticus/metabolismo , Lacticaseibacillus paracasei/metabolismo , Propionatos , Proteólise , Compostos Orgânicos Voláteis/análiseRESUMO
BACKGROUND: Serrano Catarinense cheese is a raw bovine milk cheese produced in the region of Santa Catarina, Brazil. Twelve representative strains of Leuconostoc isolated from 20 samples of this artisanal cheese were selected and submitted for evaluation of the acidifying, proteolytic, autolytic, aminopeptidase and lipolytic activities, NaCl and acid resistance, production of dextran and biogenic amines and antimicrobial activity. The aim was to genetically and technologically characterize the Leuconostoc strains in order to use them in mixed starter cultures for cheese manufacture. RESULTS: Leuconostoc mesenteroides subsp. mesenteroides was the species that accounted for the largest proportion of isolates of Leuconostoc genus. Two leuconostoc isolates stood out in the acidifying activity, with reduction in pH of 1.12 and 1.04 units. The isolates showed low proteolytic and autolytic activity. Most of the isolates were dextran producers, presented good resistance to the salt and pH conditions of the cheese and showed antimicrobial activity against cheese pathogen bacteria, and none of them produced biogenic amines. CONCLUSION: These results allowed the selection of five strains (UEL 04, UEL 12, UEL 18, UEL 21 and UEL 28) as good candidates for use as adjunct cultures for cheese manufacture. © 2018 Society of Chemical Industry.
Assuntos
Queijo/microbiologia , Leuconostoc/metabolismo , Animais , Aminas Biogênicas/análise , Aminas Biogênicas/metabolismo , Brasil , Bovinos , Queijo/análise , Fermentação , Leuconostoc/genética , Leuconostoc/isolamento & purificação , Leite/microbiologiaRESUMO
In this study, nineteen Lactobacillus isolated from Algerian goat's milk, 13 belonging to L. plantarum, three to L. pentosus, two to L. rhamnosus and one to L. fermentum, were examined in vitro in order to be used as adjunct culture in dairy products. The strains were tested for their proteolytic activity, sensory and safety properties. Strains LbMS16 and LbMS21 L. plantarum and LbMF25 L. rhamnosus presented the highest proteolytic activity. All the tested lactobacilli were able to grow on MRS agar containing 0.5 and 1% (W/V) of oxgall, whereas none produced biogenic amine (BA) from the four tested amino acids and were resistant to pH 2.0 and 3.0, but some strains were able to grow at pH 3.5. None of examined strains were β-haemolytic when grown in hors blood agar. Result of antibiotic resistance showed that all the strains were susceptible to penicillin, erythromycin and resistant to vancomycin. Diacetyl production was observed for two strains of L. plantarum and one of L. rhamnosus. Most of strains were able to produce pleasant flavours in fermented milk and gave a good acceptance. According to these results, the strains LbMS16, LbMS21and LbMF25 could be good candidates to be used as adjunct culture, playing a probiotic role in dairy products manufacture in Algeria.
RESUMO
A influência de culturas adjuntas sobre as características químicas e sensoriais, e sobre a proteólise do queijo Prato foi avaliada. Os queijos foram fabricados com cultura starter comercial e cepas de Lactobacillus (Lactobacillus plantarum ou Lactobacillus helveticus) como culturas adjuntas. Os queijos controle não foram adicionados de cultura adjunta. A composição química foi analisada no dia 5 após a fabricação e a proteólise nos dias 5, 25, 45 e 65 de maturação. A aceitação sensorial foi avaliada em 60 dias. Um delineamento de parcelas subdivididas foi utilizado e o experimento completo foi realizado em triplicata. Os resultados foram avaliados pela análise de variância e teste de Tukey no nível de 5% de probabilidade. Os queijos não apresentaram diferenças significativas em relação à composição química. Um aumento significativo na proteólise ocorreu durante o período de maturação para os queijos com cultura adjunta, quando comparado aos queijos sem adição desse tipo de cultura. Os queijos com Lactobacillus helveticus apresentaram médias das notas mais altas para os atributos sabor, textura e intenção de compra em comparação aos demais tratamentos. A utilização de Lactobacillus como cultura adjunta indica que a proteólise do queijo prato pode ser acelerada a fim de reduzir o seu tempo de maturação.
Influence of adjunct cultures on the chemical and sensory characteristics, and proteolysis of Prato cheese was investigated. Cheeses were manufactured using a commercial starter culture and Lactobacillus strains (Lactobacillus plantarum or Lactobacillus helveticus) as adjunct cultures. Control cheeses lacked the adjunct culture. The chemical composition was analyzed at day 5 after manufacture and the proteolysis at days 5, 25, 45 and 65 of ripening. The sensory acceptance was assessed at 60 days. A split-plot design was used and the complete experiment was carried out in triplicate. The results were evaluated by ANOVA and Tukeys test test at 5% significance level. There were no significant differences in chemical composition among the cheeses. A significant increase in proteolysis occurred during ripening period for the cheeses with adjunct culture when compared to cheeses without adjunct culture. Cheese with Lactobacillus helveticus showed higher scores for flavor, texture and purchase intent compared with the others treatments. Use of adjunct Lactobacillus suggests that the proteolysis of Prato cheese should be accelerated in order to reduce ripening period.
RESUMO
A influência de culturas adjuntas sobre as características químicas e sensoriais, e sobre a proteólise do queijo Prato foi avaliada. Os queijos foram fabricados com cultura starter comercial e cepas de Lactobacillus (Lactobacillus plantarum ou Lactobacillus helveticus) como culturas adjuntas. Os queijos controle não foram adicionados de cultura adjunta. A composição química foi analisada no dia 5 após a fabricação e a proteólise nos dias 5, 25, 45 e 65 de maturação. A aceitação sensorial foi avaliada em 60 dias. Um delineamento de parcelas subdivididas foi utilizado e o experimento completo foi realizado em triplicata. Os resultados foram avaliados pela análise de variância e teste de Tukey no nível de 5% de probabilidade. Os queijos não apresentaram diferenças significativas em relação à composição química. Um aumento significativo na proteólise ocorreu durante o período de maturação para os queijos com cultura adjunta, quando comparado aos queijos sem adição desse tipo de cultura. Os queijos com Lactobacillus helveticus apresentaram médias das notas mais altas para os atributos sabor, textura e intenção de compra em comparação aos demais tratamentos. A utilização de Lactobacillus como cultura adjunta indica que a proteólise do queijo prato pode ser acelerada a fim de reduzir o seu tempo de maturação.
Influence of adjunct cultures on the chemical and sensory characteristics, and proteolysis of Prato cheese was investigated. Cheeses were manufactured using a commercial starter culture and Lactobacillus strains (Lactobacillus plantarum or Lactobacillus helveticus) as adjunct cultures. Control cheeses lacked the adjunct culture. The chemical composition was analyzed at day 5 after manufacture and the proteolysis at days 5, 25, 45 and 65 of ripening. The sensory acceptance was assessed at 60 days. A split-plot design was used and the complete experiment was carried out in triplicate. The results were evaluated by ANOVA and Tukeys test test at 5% significance level. There were no significant differences in chemical composition among the cheeses. A significant increase in proteolysis occurred during ripening period for the cheeses with adjunct culture when compared to cheeses without adjunct culture. Cheese with Lactobacillus helveticus showed higher scores for flavor, texture and purchase intent compared with the others treatments. Use of adjunct Lactobacillus suggests that the proteolysis of Prato cheese should be accelerated in order to reduce ripening period.