DIFFERENCES BETWEEN FAT-RELATED CHARACTERISTICS OF SOUR CREAM AND SOUR CREAM ANALOGUES

Modiﬁ cation of dairy products’ fat composition or replacement by other fats are common practices in the industry. Products in which milkfat is partially or wholly substituted by vegetable fats are deﬁ ned as dairy analogues. This study delivers gap-ﬁ lling information about sour cream analogues in nutritional aspects, focusing on the fat-related attributes. Analogue sour creams contained 29.6% less saturated fatty acids, 88.4% less cholesterol and 88.7% more mono-and poly-unsaturated fatty acids than the sour creams. Trans fatty acids were present in both products, which could not be linked to artiﬁ cial hydrogenation in either case. Digestibility of the examined samples might be diﬀ erent, as sour creams had more short and medium chain fatty acids than the analogues. Overall, sour cream analogues, besides serving as an alternative to sour cream, have particular advantages based on their nutritional values.

Consumption of dairy products causes diffi culties for a signifi cant part of the society because of their allergen, lactose, and cholesterol content and/or these products are not aff ordable for some due to their price (K et al., 2011).Furthermore, in the last few decades, the perception of milk's and dairy products' nutritional benefi ts declined as milkfat consumption was associated with atherosclerosis and heart diseases (E et al., 2008).Between the 1940s and 1990s, dietary cholesterol (and also saturated fatty acid intake) was considered as one of the main causes of cardiovascular diseases, which lead to the excessive promotion of lipid-lowering dietary recommendations (M N , 2014).Nutritionists argue that instead of avoiding cholesterol, we should focus on maintaining the balance of absorbed and synthesised amounts, also, several studies have shown that dietary cholesterol does not signifi cantly increase the risk of heart conditions in case of healthy individuals (F , 2012; M N , 2014).A minor part of the population indeed needs to reduce its intake, but the majority will unnecessarily deprive themselves of a highquality protein source such dairy products (F , 2012).A recent study revealed that the two most important attributes of dairy products for consumers are low fat content and being cholesterol-free (P et al., 2016), which suggest that the public is still extremely interested by fats used in these commodities.
Reduction of milkfat content, modifi cation of milk's and dairy products' fat composition, or replacement by other fats are common practices in the industry.Products in which milkfat is partially or wholly substituted by vegetable fats are defi ned as dairy analogues (FAO/WHO F S , 2019).Ingredients of plant origin used in these products are cheaper; therefore, the main reason for dairy analogue production is cost-eff ectiveness.
Traditional sour cream is made from only two ingredients, cream and bacterial cultures: the acidifi cation is done by lactic acid bacteria that also provide the distinctive taste and texture of sour cream (S , 2001).One type of sour cream analogues is usually made from skimmed milk mixed with vegetable fat and acidifi ed by the bacterial culture, which is the most common practice among Hungarian manufacturers.In other countries, beside milkderived components, producers usually add water and food additives.There are also sour cream analogues that are made exclusively from vegetable sources (H , 2011; N et al. 2015).
Substitution of highly valuable milkfat with vegetable fats aff ects not only the price of the product, but technological aspects should be considered, too.Milkfat has a complex fatty acid composition, which eventuate a nearly inimitable melting profi le; however, producers handle suitable melting characteristics as a primary selection criterion in regard of vegetable fats and use most frequently palm fat or coconut oil in dairy analogues (H , 2011).Similarly to milkfat (and generally dairy products), palm fat and other so-called tropical oils were linked to the risk of coronary heart disease (CHD) in the 1980s, which triggered campaigns that highlighted saturated fat (SAFA) content and demanded all palm fat to be removed from food products (M N , 2010).The need for an appropriately stable fat could only met by partial hydrogenation of vegetable oils, which in turn contained trans fatty acids.Industrially produced trans fatty acids were proved to greatly contribute to the emergence of CHD, and several countries limited its intake, in parallel, public awareness of the risk became high (M N , 2010; D L , 2016).In the case of trans fats, it should be noted that milkfat naturally contains trans fatty acids produced by microbes in the animal's rumen.While there are several studies that confi rm the negative health eff ects of industrial trans fats (iTFA), the harmfulness of ruminant trans fatty acids (rTFA) is still disputed.Nevertheless, if rTFAs had been able to cause the same changes in human serum lipids, possibly their dietary intake would not exceed a level that is considered to be concerning (D L , 2016).As a conclusion of the above, a lot of questions are raised when discussing which is better: dairy products that naturally contain milkfat or the analogues with substitute palm fat.The results of this comparison will give a clearer picture about advantages and disadvantages of dairy analogues.

Materials and methods
For the analysis, products of three diff erent Hungarian dairy producers (coded as A, B, and C) -having a selection in both product lines -were chosen: one traditional sour cream and one sour cream analogue from each, with 20% fat content.Table 1 presents the lists of ingredients of the products.Products were purchased from a local food store in Budapest, Hungary, during April of 2018.Samples were prepared in duplicate for each examination.
The analytical examinations were carried out in the accredited laboratory of the Hungarian National Food Chain Safety Offi ce (NFCSO), National Reference Laboratory of Food and Feed Safety Directorate, using accredited standard methods.The protein content of the products was determined based on the nitrogen content by Kjeldahl method (MSZ 1385(MSZ :1987)).Amount of lactose was measured by high-performance liquid chromatography based on the work of D and O (1979), which was carried out after sample clarifi cation by separation of interfering compounds adding Carrez reagents.Samples' fat content was tested based on the Röse-Gottlieb method (MSZ 9602:1984 Chapter 1).Lactic acid bacteria number was examined on de Man, Rogosa and Sharpe agar by culturing at 30 °C (ISO 15214:2005).Fatty acid composition (including the amount of SAFA, MUFA, PUFA, omega-3 and -6 fatty acids) (ISO 5508:1992), trans fatty acids (EN ISO 15304:2002), as well as cholesterol content (EN ISO 12228-1:2014) were analysed using various gas chromatographic methods.Sample preparation for fatty acid composition analysis and trans fatty acid content determination were based on the formulation of fatty acid methyl esters (EN ISO 5509: 2000 Chapter 5).Cholesterol content measurement was preceded by a saponifi cation step and purifi cation of desmethyl sterol fraction on a thin layer plate.Parameters of the chromatographic methods are shown in Table 2. Signifi cance of the diff erences between the results of sour creams and sour cream analogues were analysed by one-way ANOVA (Analysis of Variance), which analysis was carried out using the IBM SPSS 23.0 statistical software (IBM C , 2015).The confi dence level was set to 95%.

Results and discussion
Proteins and carbohydrates remain dissolved in the serum phase of the skimmed milk after milkfat separation, as well as water-soluble vitamins and a notable amount of the minerals (E et al., 2008), therefore the examined sour cream analogues should contain nearly the same amount of these nutrients if the eff ectiveness of the fat separation method used by the producer is appropriate.This has been verifi ed by our results as the amounts of protein, fat, and lactose (the carbohydrate content of milk is almost completely derived from lactose) did not diff er signifi cantly (F protein =4.55, p protein =0.10; F fat =3.06, p fat =0.16; F lactose =1.00, p lactose =0.37) among the two product categories (Table 3).Fat content of the analysed products was compliant to the requirements (C A H , 2014).This also applies to the lactic acid bacteria content (Table 3), in which no statistically confi rmed diff erence was observed (F=0.76,p=0.43).The amount of each fatty acid identifi ed in the samples is detailed in Table 4.The results of sour creams highlight the complex fatty acid composition of milkfat, while sour cream analogues contain a less versatile set of fatty acids (in accordance with the composition of palm fat).Because a small amount of milkfat remains in the skimmed milk base, some fatty acids (C4-C14 and C19-C24 chain length) rather characteristic of milkfat than palm fat are present in the analogues.
The results of the analysis of fat-related characteristics are shown in Table 5.As expected from the main attributes of milkfat and palm fat, the diff erence between the quantity of SAFA (F=1258.95,P<0.001), MUFA (F=522.27,P<0.001), PUFA (F=913.59,P<0.001), omega-3 (F=12.39,P=0.024), omega-6 (F=982.40,P<0.001), trans (F=50.84,p=0.002), short chain (F=680.84,P<0.001), medium chain (F=877.45,P<0.001), and long chain (F=238.65,P<0.001) fatty acids, and the amount of cholesterol (F=709.78,P<0.001) is signifi cant in sour creams and sour cream analogues.As it is shown in Table 5, saturated fatty acids are dominant in sour cream, while in the analogue products the ratio of saturated and unsaturated fatty acids is more balanced.Saturated fatty acids are less effi ciently absorbed, moreover, they increase the risk of CHD and CVD (cardiovascular diseases) more than unsaturated fatty acids (R et al., 2001).In addition, they contribute to the development of obesity and metabolic syndromes (E et al., 2008).The eff ort to mitigate saturated fatty acid intake is an offi cial recommendation of WHO (World Health Organization) (WHO, 2018), for which dairy analogues may be suitable.In these aspects, the chain length is also an infl uencing factor -the longer the chain, the more diffi cult it is to be solubilised in the intestine (R et al., 2001).Due to the palm fat in our sour cream analogue samples, the majority (98%) of the fatty acids have long chain, the medium and short chain fatty acids are possibly derived from the minor amount of milkfat that comes from the skimmed milk base (Table 4).Furthermore, many studies presented that the short and medium chain saturated fatty acids in milkfat have positive eff ects on human health (e.g.butyric acid is an anticarcinogen, caprylic, capric, and lauric acids have antiviral activities, etc.), also only three of the twelve major SAFAs of milkfat (lauric, myristic, and palmitic acids) may be involved in raising the cholesterol level of plasma (E et al., 2008).
Sour creams contain less omega-6 and more omega-3 acids than sour cream analogues, however, in both product categories omega-6 fatty acids are predominant compared to omega-3 fatty acids (Table 5), and their ratio is far from the ideal 4:1.In modern diets, the consumption of omega-6 rich fats is too excessive, which increases the risks of CVD, autoimmune diseases, and even cancer (E et al., 2008).In case of dairy and dairy analogue products, this issue could be solved by blending omega-3 rich oils (for example canola oil, fl axseed oil) to the products, while appropriate feeding could also contribute to a better balance (A et al., 2017).Isomerism is another important question regarding unsaturated fatty acids: fat content of sour cream samples consisted of more than 2% of trans fatty acids as milkfat naturally contains rTFA.In sour cream analogues, TFA ratio is below 0.5%.This amount is very likely originated from the milk base, since palm fat does not require hydrogenation for milkfat replacement.This is confi rmed by the fact that elaidic acid, the presence of which is one of the main signs of hydrogenation, was found in the analogues below the detection level.
As discussed in the introduction, there is no evidence that rTFA is as harmful as iTFA.In legislation, many countries made eff ort to diff erentiate rTFA and iTFA, and set up limitations only for the artifi cial trans fatty acids (Z -G K , 2019).
Low cholesterol content could be listed as one of the advantages of sour cream analogue consumption as cholesterol in the analogue is only one-eighth of the amount measured in sour cream (Table 5).This amount is likely derived from the skimmed milk base, since Unauthenticated | Downloaded 09/15/23 07:34 PM UTC Acta Alimentaria 49, 2020 vegetable fats contain negligible amounts of cholesterol (S et al., 2015).In the light of the average daily intake of cholesterol (approx.260-290 mg/day) (S et al., 2015) and the recommended level (lower than 200-300 mg/day) (K et al., 2012), substituting ordinary sour cream with analogue could be benefi cial for restraining cholesterol intake.

Conclusions
Our study provides gap-fi lling information on the comparison of a dairy product and its dairy analogue regarding their nutritional aspects.According to our fi ndings, no signifi cant diff erences could be found between sour cream and sour cream analogues in protein, lactose, fat, and lactic acid bacteria contents.However, analysis of the composition of fat content has proven that analogue products contained less saturated fatty acids and cholesterol and more mono-and polyunsaturated fatty acids.Sour cream analogue products contain signifi cantly less trans fatty acids, nevertheless, it should be noted rTFAs are diff erentiated from iTFAs by law in many countries, and their ratio in food products is not limited.Although these characteristics suggest that people in risk of CHD could substitute sour cream consumption with analogues, the digestibility of the two products in terms of carbon chain length of the fatty acids might be diff erent.Although, none of the products contain omega-6 and omega-3 fatty acids in the ideal balance, sour creams could deliver a ratio of 5.43:1, while analogue samples contain these components in a 44.33:1 ratio.
It should be taken into account that producers are stressed to consider using other fats than palm fat for dairy analogues due to the demand for improved fatty acid composition and sustainability issues (e.g.avoiding tropical oils).Fortifi cation of dairy analogues with vitamins, minerals, or probiotics could be a way for progression as well.
Overall, we can conclude that sour cream analogues, based on their nutritional values, can serve as an alternative product of sour cream, especially when consumed in larger quantities.In the future, more health related innovations are expected in the fi eld of dairy analogues, but the exact role of this product category in the human diet should be outlined by further clinical research, which is currently scarce.

Table 1 .
Components of the sour cream and sour cream analogue products from three diff erent producers (A, B, and C) as indicated on the label Unauthenticated | Downloaded 09/15/23 07:34 PM UTC

Table 2 .
Details of the used gas and high-performance liquid chromatographic methods Unauthenticated | Downloaded 09/15/23 07:34 PM UTC

Table 4 .
Fatty acid composition of sour cream and sour cream analogue samples (N=12)

Table 5 .
Fat-related diff erences between sour cream and sour cream analogue (N=12)