Research On The Application Of Lactobacillus Casei LC2W In Cheddar Cheese

Cheddar cheese, which can deliver probiotics into the human intestine, is a goodcarrier of probiotics because of its higher pH value, greater buffering capacity, loweroxygen content, higher fat content and denser matrix of the texture. In addition, cheddarcheese maintains a dynamic microorganism during it’s ripening. And the starter lacticacid bacteria (Lactococcus) will have a rapid decrease with the cheddar cheese ripening,while the non-starter lactic acid bacteria(especially Lactobacillus) will have a hugeincrease. In this paper, Lactobacillus casei LC2W (LC2W) was selected as the probioticof cheddar cheese. The survival of LC2W and the influence of LC2W on the quality ofcheddar cheese were studied.Probiotic LC2W was used as an adjunct in the production of probiotic cheddarcheese, and without LC2W cheeses were made as a control group simultaneously. Then,the survival of LC2W in cheddar cheese, the microbial communities of Cheddar Cheese,the proteinsis and the textural properties were researched during ripening period of180days at6℃. Moreover, the sensory evaluation of different types of cheeses was studiedafter180days ripening.Results: In the180-days ripen cheddar cheese, the LC2W could survive in anamount of over1×10~7CFU/g that meets the requirement of the probiotic foods in theaspect of the viable probiotic number. With the extension of the ripening time,proteolysis of both trial and control groups was strengthened. The pH4.6water solublenitrogen,12%trichloroacetic acid soluble nitrogen and5%phosphotungstic acidsoluble nitrogen of cheddar cheese (expressed as a percentage of total nitrogen content,WSN/TN, TCA-SN/TN and PTA-SN/TN, respectively) were increased during ripening.Both the WSN/TN and PTA-SN/TN of the probiotic cheddar cheese were significantlyhigher than control cheese (p≤0.05) in the end of ripening(150d,180d). WSN/TN,TCA-SN/TN and PTA-SN/TN determination, pH4.6water insoluble proteinUrea-PAGE pattern analysis and pH4.6water insoluble polypeptide RP-HPLC peptidemapping analysis showed that the LC2W could improve α-casein degradation rate and increase the degradation degree.With the extension of cheddar cheese ripening, the hardness, adhesiveness andchewiness of cheese gradually increased, while the resilience gradually reduced. Thehardness and chewiness of probiotic cheddar cheese were significantlyhigher (p≤0.05)than the control group at ripening60,90,120,150and180d. But the cohesiveness andadhesiveness of probiotic cheddar were significantly lower (p≤0.05) than control groupcheddar cheese at ripening150d and180d. In addition, added LC2W had a large changein cheese cohesiveness, which was gradually decreased with the ripening time. But thecohesiveness of the control group cheese was gradually increased with the extension ofthe ripening time. During cheddar cheese ripening, the springiness of probiotic cheddarhad no significant difference compared with control groups (p>0.05). After180daysripening, the results of sensory evaluation showed that probiotics cheddar cheese andcontrol group cheddar cheese also had no significant difference (p>0.05).Conclusion: The probiotics LC2W in the cheddar cheese could maintain highconcentrations and long survival, and the LC2W added had no important defects effecton cheese quality. All above investigations showed that the LC2W had the developmentpotential as the probiotic of probiotic cheddar cheese.