Science and technology of cultured cream products: A review

Rheological, Physicochemical, Microbiological, and Aroma Characteristics of Sour Creams Supplemented with Milk Protein Concentrate

Milk protein concentrate (MPC) is widely used to enhance the stability and texture of fermented dairy products. However, most research has focused on yogurt products, and the effects of MPC on sour cream characteristics remain unknown. Therefore, we investigated the effects of different MPC levels (0%, 1%, 2%, and 3% w/w) on the rheological, physicochemical, microbiological, and aroma characteristics of sour creams in this study. We found that MPC supplementation stimulated the growth of lactic acid bacteria (LAB) in sour creams, resulting in higher acidity than that in the control sample due to the lactic acid produced by LAB. Three aroma compounds, acetaldehyde, diacetyl, and acetoin, were detected in all sour cream samples. All sour creams showed shear-thinning behavior (n=0.41-0.50), and the addition of MPC led to an increase in the rheological parameters (η_a,50, K, G', and G″). In particular, sour cream with 3% MPC showed the best elastic property owing to the interaction between denatured whey protein and caseins. In addition, these protein interactions resulted in the formation of a gel network, which enhanced the water-holding capacity and improved the whey separation. These findings revealed that MPC can be used as a supplementary protein to improve the rheological and physicochemical characteristics of sour cream.

Development of sour cream with vegetable oils using a food emulsion stabilised by an emulsifying complex

This scientific work describes the research that aims to study the use of a finely dispersed, aggregately stable food emulsion with a mass fraction of blended oil of 50% and xanthan gum in the composition of sour cream with vegetable oils as an analogue of traditional sour cream. The samples of fat-containing fermented-milk bases as a component of sour cream with vegetable oils with a fat content of 10-20% were obtained using two methods. The first method consists in normalising the fat content of the fermented-milk base obtained by fermentation of skimmed cow's milk with a food emulsion, and the second one – is in the fermentation of a normalised mixture consisting of a food emulsion and skimmed cow's milk. When comparing the duration of fermentation of skimmed cow's milk and normalised mixtures with a fat content of 10 to 20%, it was established that in order to achieve the minimum value of the titrated acidity of the clot of 60 °T, the duration of fermentation of skimmed cow's milk is 6 hours, of a normalised mixture with a fat content of 10% – 8 hours, 15% – 12 hours, 20% – 16 hours. According to the organoleptic quality indicators, the samples of fat-containing fermented-milk bases with a fat content of 20%, obtained by two methods, had an indiscrete but unsuitable thick consistency, which was adjusted using xanthan gum. According to the organoleptic quality indicators, it was established that in order to obtain a sour cream with vegetable oils with an indiscrete and thick consistency, 0.15% of xanthan gum should be added to the fat-containing base obtained by the first method, and 0.20% – to the fat-containing base obtained by the second method. The study of determining the content of polyunsaturated fatty acids in sour cream with vegetable oils with a fat content of 20% shows an increased content of omega-3 and omega-6 fatty acids – 2.13% and 10.88%, respectively, compared to sour cream obtained by the traditional technology.

Photosensitized oxidation of cholesterol and altered oxysterol levels in sour cream: Effects of addition of cucumber pickles

The aim of this research was to examine whether sour cream (18% fat) is an exogenous source of oxysterols and whether it is possible to improve its antioxidative properties and to modulate cholesterol transformation by adding cucumber. To determine whether cucumber modifies the properties of sour cream, fresh cucumber or cucumber pickle (pH 3.3; 1.5% lactic acid) was added in an amount of 20%. The sour cream samples were then stored under light (450 lx, 590 cd, 120 lm) for 3 wk. After storage, the addition of the cucumber pickle increased total mesophilic aerobic bacteria from 7.5 to 9.3 log cfu/g and increased the l-lactic acid content from 6.1 to 9.7 g/L. The total conjugated linoleic acid content in sour cream with cucumber pickle also increased to 4.5 mg/g fat after storage, whereas the cholesterol content decreased to 3.44 g/kg fat. Importantly, with the addition of cucumber pickle, the total content of cholesterol oxidization products (COP) did not change after storage (1.7 mg/kg fat). By contrast, the total COP content in the control sour cream sample increased from 1.7 to 7.3 mg/kg fat over 3 wk of storage. The dominant COP before and after storage was 7β-hydroxycholesterol. Thus, despite exposure to light, adding cucumber pickle to sour cream modulates cholesterol transformation and effectively inhibits the formation of oxysterols.

Effect of galactomannan addition on rheological, physicochemical, and microbial properties of cultured sour cream

Sour cream is a popular fermented dairy product and galactomannans are widely used in the food industry to improve texture and stability. In this study, it was investigated the effects of different galactomannans (guar gum (GG), locust bean gum (LBG), and GG/LBG) on the rheological, physicochemical, and microbial properties of sour creams. All the sour cream samples had similar pHs (4.55-4.57), acidity (0.83-0.86%), and lactic acid bacteria viable counts (8.08-8.15 log CFU/g) after fermentation. The rheological parameters (η_a,50, K, G', G″, and tan δ) of the sour creams increased after the addition of galactomannans. The sour cream with GG showed higher η_a,50, K, G', and G″ values than the sour cream with LBG. Furthermore, the combination of galactomannans (GG/LBG) did not have any synergistic effect on the sour cream. The water-holding capacity of sour creams was enhanced by the addition of galactomannans, resulting in reduced syneresis.

Isolation of Lactococcus lactis ssp. cremoris LRCC5306 and Optimization of Diacetyl Production Conditions for Manufacturing Sour Cream

The sensory properties and flavor of sour cream are important factors that influence consumer acceptability. The present study aimed to isolate lactic acid bacteria with excellent diacetyl production ability and to optimize the fermentation conditions for sour cream manufacture. Lactococcus lactis ssp. cremoris was isolated as a lactic acid bacterium derived from raw milk. This strain showed the greatest diacetyl production among other strains and was named LRCC5306. Various culture conditions were optimized to improve the diacetyl production of LRCC5306. The highest diacetyl production was found to be at 105.04±2.06 mg/L, when 0.2% citric acid and 0.001% Fe2+ were added and cultured at 20°C for 15 h. Based on the optimal cultivation conditions, sour cream was manufactured using LRCC5306, with a viable count of 1.04×108 CFU/g and a diacetyl concentration of 106.56±1.53 mg/g. The electronic tongue system was used to compare the sensory properties of the sour cream; the fermented product exhibited sweetness and saltiness which was similar to that of an imported commercial product, but with slightly reduced bitterness and a significantly greater degree of sour taste. Therefore, our study shows that if cream is fermented using the LRCC5306, it is possible to produce sour cream with greatly improved sensory attractiveness, resulting in increased acceptance by consumers. Since this sour cream has a higher viable count of lactic acid bacteria, it is also anticipated that it will have a better probiotic effect.