Viability of Bifidobacterium longum in cheddar cheese curd during manufacture and storage: effect of microencapsulation and point of inoculation

International audienceThe goal of this study was to assess the effect of methods of inoculation on the viability of probiotic bacteria during cheddar cheese manufacture as well as their stability during storage. Bifidobacterium longum ATCC 15708 was freeze-dried and microencapsulated by spray-coating. The effect of inoculation of free whole cell or microencapsulated cells at three points during manufacture (milk before renneting, at cheddaring or at salting) on the viable counts in cheese and whey was investigated. Microencapsulation had no effect on viable counts, chemical parameters (lactose, lactic acid, total nitrogen, nitrogen soluble in TCA, moisture) or sensory properties during manufacturing or storage of the fresh cheeses for 14 days. Inoculation of the bifidobacteria in milk before renneting resulted in higher viable counts in comparison to other points of inoculation. Bifidobacteria added at the salting step, which survived pressing, were subsequently more stable during storage than those inoculated in milk. The stability of B. longum 15708 during storage was greater in the pressed cheeses that in the free curds. The results of this study provides technological data for cheese makers on the optimum point of inoculation as well as the benefit of pressing the curds in order to ensure high levels of probiotics in fresh cheddar cheese

Interactions of phenolic compounds with milk proteins

International audienceThis study showed that phenolic compounds mainly interacted with casein rather than whey protein. To prove this, the molecular interactions between phenolic compounds and milk proteins, such as casein and whey proteins, were investigated by measuring changes in their aggregate sizes of molecules. Size-exclusion chromatography was performed to determine the aggregate sizes of milk proteins. Results showed that when casein was mixed with an extract of green tea, grape, or cranberry, the aggregate size of casein increased as a result of chemical interactions between casein and the phenolic compounds. Meanwhile, only a negligible change in the aggregate size was observed when whey protein was mixed with phenolic compounds, implying little interaction. The higher affinity of these polyphenolic compounds with casein proteins was correlated with the high recovery potential of polyphenolic compounds in the cheese-making process as caseins are the main proteins in cheese curd. These results could help to design manufacturing processes of functional dairy products that improve yield and quality attributes

Viability of bifidobacterium longum in cheddar cheese curd during manufacture and storage: effect of microencapsulation and point of inoculation

International audienceThe goal of this study was to assess the effect of methods of inoculation on the viability of probiotic bacteria during cheddar cheese manufacture as well as their stability during storage. Bifidobacterium longum ATCC 15708 was freeze-dried and microencapsulated by spray-coating. The effect of inoculation of free whole cell or microencapsulated cells at three points during manufacture (milk before renneting, at cheddaring or at salting) on the viable counts in cheese and whey was investigated. Microencapsulation had no effect on viable counts, chemical parameters (lactose, lactic acid, total nitrogen, nitrogen soluble in TCA, moisture) or sensory properties during manufacturing or storage of the fresh cheeses for 14 days. Inoculation of the bifidobacteria in milk before renneting resulted in higher viable counts in comparison to other points of inoculation. Bifidobacteria added at the salting step, which survived pressing, were subsequently more stable during storage than those inoculated in milk. The stability of B. longum 15708 during storage was greater in the pressed cheeses that in the free curds. The results of this study provides technological data for cheese makers on the optimum point of inoculation as well as the benefit of pressing the curds in order to ensure high levels of probiotics in fresh cheddar cheese

Encapsulation of coenzyme Q10 in a simple emulsion-based nutraceutical formulation and application in cheese manufacturing.

International audienceCoenzyme Q10 (CoQ10) was encapsulated successfully in a nutraceutical formulation composed of calcium caseinate, flaxseed oil and lecithin. The effect of CoQ10 on the physico-chemical stability of emulsions was compared to emulsions without CoQ10. According to ATR-FTIR analysis, emulsions were found to be more stable in the presence of CoQ10. The emulsion with CoQ10 was used as a functional cream in the cheese making process. The retention rate of CoQ10, composition and cheese yield were also determined. Quantification of CoQ10 by HPLC showed that the retention of this lipophilic agent into cheese matrix was 93% and equivalent to the total lipid retention. Protein retention and cheese yield were not affected by the addition of the functional cream. For the first time, CoQ10 has been encapsulated in a cheese matrix, hence demonstrating that CoQ10 could be used in the development of functional cheeses

Polyphenolic compounds as functional ingredients in cheese

International audienceA functional cheese product containing polyphenolic compounds was developed, and the polyphenolic retention efficiency and antioxidant property of the product evaluated. Single phenolic compounds, including catechin, epigallocatechin gallate (EGCG), tannic acid, homovanillic acid, hesperetin and flavones, and natural crude compounds, such as grape extract, green tea extract, and dehydrated cranberry powder, were added as functional ingredients to the prepared cheese. They evidenced different levels of retention in the cheese curds which varied widely in terms of their effects on gel-formation behaviours, depending on their molecular properties and their hydrophobicity was particularly relevant. Cheese curds with polyphenolic compounds at a concentration of 0.5 mg/mL showed effective free radical-scavenging activity. The nutritional value of cheese product was improved by adding bioactive phenolic compounds to the cheese curd. These results suggest that we may apply this approach to other dairy products for better quality and functionality of the products

Enrichment of cheese with vitamin D3 and vegetable omega-3

International audienceEncapsulation technology provides many benefits to the food fortification: protection from oxygen and light, a best dispersion and biodisponibility, etc. In this study, vitamin D3 was encapsulated in two flaxseed oil emulsion formulations. Emulsions were stabilised with calcium caseinate in presence or absence of lecithin and used to standardise cheese milk. The use of flaxseed oil rich in alpha-linolenic acid allows fortifying the cheese in omega-3 and other polyunsaturated fatty acids (PUFA). Cheese yield and retention rate of proteins, fats and bioactive component were determined. Quantification of vitamin D3 and chemical stability of cheeses were performed up to 90 days of storage at 4 °C. Recovery level of vitamin D3 in cheese was, respectively, 91 and 84% in the presence or absence of lecithin. The encapsulation of vitamin D3 in the cheese in the form of emulsified particles of oil containing lecithin increased retention and stability of the vitamin in the curd. The fortification of cheese with vitamin D3 and PUFA had a positive impact on the composition, yield and chemical stability of the resultant cheese

Production and characterization of Cheddar-type cheese enriched with green tea extract

International audienceGreen tea polyphenols are known for their antioxidant properties. They also interact with milk proteins, suggesting good retention in the cheese matrix. The objective of this study was to evaluate the effect of green tea extract (GTE) enrichment on the organoleptic and physicochemical properties of Cheddar-type cheese during storage. GTE was added to milk at concentrations of 0, 1, and 2 g.kg−1 and cheeses were produced on a pilot scale. An average polyphenol retention coefficient of 0.63 was obtained in cheese. Total protein, fat, micellar calcium content, and yield of cheese were not significantly affected by GTE addition (P > 0.05). However, cheese moisture decreased by 1.9% with the addition of GTE at a concentration of 2 g.kg−1 of milk. Enrichment with GTE significantly affected the color of Cheddar-type cheese (P ≤ 0.05). A loss of lightness (L* value) and an increase in redness (a* value) and yellowness (b* value) were observed. Cheeses enriched with GTE showed higher hardness and a loss of cohesiveness and springiness, which is indicative of alteration of the paracasein matrix. Cheese sensory properties were evaluated by trained panelists using a ranking test. A decrease in the typical Cheddar flavor and an increase in the overall flavor intensity and the astringency of cheese were observed with the addition of GTE. The addition of GTE at a concentration of 1 or 2 g.kg−1 of milk increased the antiradical activity of cheese by 25 and 44%, respectively (P ≤ 0.05). GTE enrichment of Cheddar-type cheese could result in new products with increased health benefits