Evidence of a relationship between autolysis of starter bacteria and lipolysis in Cheddar cheese during ripening

Abstract

Cell viability, autolysis and lipolysis were studied in Cheddar cheese made using Lactococcus lactis subsp. cremoris AM2 or Lactococcus lactis subsp. cremoris HP. Cheddar cheese was made in triplicate over a 3 month period and ripened for 238 days at 8 °C. Cell viability in cheese was lower for AM2 (a non-bitter strain) than for strain HP (a bitter strain). Autolysis, monitored by the level of the intracellular marker enzyme, lactate dehydrogenase (EC 1.1.1.27) in cheese ‘juice’ extracted by hydraulic pressure, was much greater in the cheese made using AM2 than that made with HP. Lipolysis was determined by the increase during ripening of individual free fatty acids (FFA) from butyric (C4[ratio ]0) to linolenic acid (C18[ratio ]3) measured using a high performance liquid chromatographic technique. Levels of individual FFA from butyric (C4[ratio ]0) to linolenic (C18[ratio ]3) acids increased significantly (P<0·05) during ripening in cheeses made with either starter culture. Palmitic (C16[ratio ]0) and oleic (C18[ratio ]1) acids were the most abundant FFA throughout ripening in all cheeses. Levels of caprylic (C8[ratio ]0), myristic (C14[ratio ]0), palmitic (C16[ratio ]0) and stearic (C18[ratio ]0) acids were significantly higher (P<0·05) in cheeses manufactured with Lc. lactis subsp. cremoris AM2 than in cheeses manufactured with Lc. lactis subsp. cremoris HP. Differences in levels of lipolysis between strains was not due to differences in the specific lipolytic or esterolytic activities in cell free extracts of the strains as measured by activity on triolein (lipase) and p-nitrophenylbutyrate (esterase) substrates. Therefore, evidence is provided for a relationship between the extent of starter cell autolysis and the level of lipolysis during Cheddar cheese ripening.

Lipolysis and sensory characteristics of Cheddar cheeses ripened using different temperature-time treatments

“…The results obtained for relative distribution of individual FFA in this study were identical to those of many other studies involving Cheddar cheese [4,35,36,47,51]. The actual levels of individual FFA may be slightly higher than those reported for previous studies using similar ripening temperatures; however, this apparent discrepancy may be due to the higher moisture content of the cheeses used in this study or differences in the lipase/esterase activity of the starter cultures used.…”

“…Identical trends have been reported previously for the relative concentrations of palmitic and oleic acids in maturing Cheddar cheese [4,47]. At 60 d of ripening, there were no significant (P > 0.05) differences between the total FFA (Σ(C 4:0 -C 18:3 )) content of any of the 5 cheeses A, B, C, D or E, with levels varying from 4005 to 4151 mg·kg -1 for cheeses A and B, respectively.…”

“…The use of LAB starter cultures that undergo autolysis early in ripening (e.g., Lactococcus lactis subsp. cremoris AM2) also results in increased accumulation of free fatty acids in Cheddar cheese [4].…”

Evaluation of proteolytic and physicochemical changes during storage of fresh Panela cheese from Queretaro, Mexico and its impact in texture

“…Organic acids are the major product of carbohydrate metabolism; however, important flavor compounds are also produced as a result of hydrolysis of milk fat during lipolysis. In Panela cheese, PA and BA were used as an activity indicator of non-starter lactic acid bacteria (NSLAB), indigenous milk lipase (mainly lipoprotein lipase) and microbes developed during storage and ageing (Collins, McSweeney, & Wilkinson, 2003). Amounts of organic acids produced were, as expected, negatively correlated with pH changes, but only PA showed significant correlation (p 5 0.05).…”

Queijo Parmesão: caracterização físico-química, microbiológica e microestrutura

“…O menor valor foi 3,26% ± 0,11, encontrado na amostra L 2 aos 30 dias, e o maior valor na amostra L 1 , com 12,30% ± 0,15 após (Figura 7a, b), os glóbulos de gordura apresentam tamanhos maiores quando comparados àqueles observados nos demais períodos (Figuras 7f, g, h, i). Possivelmente, o surgimento dos pequenos glóbulos de gordura pode ser consequência da ação de lipases microbianas ativas na matriz do queijo durante a maturação (COLLINS; McSWEENEY; WILKINSON, 2003) e/ou provenientes do tratamento aplicado no processamento desse derivado lácteo (LOPEZ, 2005;LOPEZ;CAMIER;GASSI, 2007). Embora o tratamento térmico do leite seja indispensável para garantir a qualidade sanitária na fabricação de queijos, quando é realizado de forma severa, pode afetar a estrutura do coágulo, sendo perceptível, mais tarde, na microestrutura do produto (PEREIRA; GOMES; MALCATA, 2009).…”