Voltammetric Determination of 5-Hydroxymethyl-2-furfural in Processed Cheese Using an Easy-Made and Economic Integrated 3D Graphene-like Electrode

The concentration of 5-hydroxymethyl-2-furfural (HMF) is an important quality-related index in milk and milk products. Fast, cost-effective and environmentally friendly determination of HMF is of great significance in milk products control. In this study, a three-dimensional (3D) graphene-like surface (3DGrls) was successfully prepared within 5 min by an electrochemical amperometric pretreatment on a pencil graphite electrode (PGE). The fast-obtained 3D graphene-like surface increased the electrode surface area and enhanced the electron transfer capability without the addition of any harmful chemicals. The morphology and chemical composition of the obtained electrode were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The results found that the electrochemical response to HMF at the prepared 3DGrls/PGE was 34 times higher than that at PGE. The modified electrode showed a good linear response to HMF in a concentration range of 0.35~116 μM with a low limit of detection (LOD) of 0.099 μM. The integrated electrode also exhibited excellent stability and wonderful antifouling property. Furthermore, the 3DGrls/PGE was successfully applied for the determination of HMF in three processed cheese samples with satisfactory results.

Comparison of Cheese Aroma Intensity Measured Using an Electronic Nose (E-Nose) Non-Destructively with the Aroma Intensity Scores of a Sensory Evaluation: A Pilot Study

Cheese aroma is known to affect consumer preference. One of the methods to measure cheese aroma is the use of an electronic nose (e-nose), which has been used to classify cheese types, production areas, and cheese ages. However, few studies have directly compared the aroma intensity scores derived from sensory evaluations with the values of metal oxide semiconductor sensors that can easily measure the aroma intensity. This pilot study aimed to investigate the relationship between sensory evaluation scores and e-nose values with respect to cheese aroma. Five types of processed cheese (two types of normal processed cheese, one type containing aged cheese, and two types containing blue cheese), and one type of natural cheese were used as samples. The sensor values obtained using the electronic nose, which measured sample aroma non-destructively, and five sensory evaluation scores related to aroma (aroma intensity before intake, during mastication, and after swallowing; taste intensity during mastication; and remaining flavor after swallowing (lasting flavor)) determined by six panelists, were compared. The e-nose values of many of the tested cheese types were significantly different, whereas the sensory scores of the one or two types of processed cheese containing blue cheese and those of the natural cheese were significantly different. Significant correlations were observed between the means of e-nose values and the medians of aroma intensity scores derived from the sensory evaluation testing before intake, during mastication, and after swallowing. In particular, the aroma intensity score during mastication was found to have a linear relationship with the e-nose values (Pearson’s R = 0.983). In conclusion, the e-nose values correlated with the sensory scores with respect to cheese aroma intensity and could be helpful in predicting them.

Characterization of Vegetative Bacillus cereus and Bacillus subtilis Strains Isolated from Processed Cheese Products in an Italian Dairy Plant

Processed cheese is a commercial product characterized by high microbiological stability and extended shelf life obtained through the application of severe heat treatment. However, spore-forming bacteria can survive through thermal processes. Among them, microorganisms belonging to Bacillus genus have been reported. In this study, we examined the microbiological population of the first hours’ production of processed cheeses in an Italian dairy plant during two seasons, between June and October 2020. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to identify bacteria colonies, allowing the isolation of Bacillus cereus and Bacillussubtilis strains. These results were further confirmed by amplification and sequencing of 16 rRNA bacterial region. A multi-locus sequence type (MLST) analysis was performed to assess the genetic similarity among a selection of isolates. The fourteen B. cereus strains showed two sequence types: ST-32 was observed in only one strain and the ST-371 in the remaining thirteen isolates. On the contrary, all twenty-one B. subtlis strains, included in the study, showed a new allelic profile for the pycA gene, resulting in a new sequence type: ST-249. For B. cereus strains, analysis of toxin genes was performed. All isolates were positive for nheABC, entFM, and cytK, while hblABCD, bceT, and ces were not detected. Moreover, the biofilm-forming ability of B. cereus and B. subtilis strains was assessed, and all selected isolates proved to be biofilm formers (most of them were stronger producers). Considering the genetical similarity between isolates, jointly with the capacity to produce biofilm, the presence of a recurring Bacillus population could be hypothesized.

Vegan Alternatives to Processed Cheese and Yogurt Launched in the European Market during 2020: A Nutritional Challenge?

Vegan alternatives to cheese (VAC) and yogurt (VAY) are fast-growing markets in Europe due to the increasing interest in plant-based alternatives to dairy products. This study aimed to take a closer look at the year 2020 and accordingly retrieved the nutritional information of dairy cheese and yogurt and their vegan counterparts for comparison. It was found that VAY (n = 182) provide more energy, total fats, and carbohydrates than dairy yogurt (n = 86), while saturated fatty acids (SFAs), sugars, and salt were not different between the two categories. Compared to dairy products (25.6%), 72.9% of the alternative products were declared low/no/reduced allergen, hence providing a larger spectrum of products to respond to consumers’ requirements. VAC (n = 114) showed high versatility of form compared to dairy (n = 115). Nutritionally, VAC have higher total fats, SFAs, and carbohydrates, but lower protein, salt, and sugar than dairy cheese. Food developers will continue to look for clean label solutions to improve the nutritional values of vegan products through the incorporation of natural ingredients, besides enhancing their taste and texture to appeal to flexitarians.

Revealing the features of the formation of the properties of processed cheese with wild onions

Processed cheeses belong to food products of high nutritional and biological value. Bioflavonoids, which are widespread in higher plants and have a number of unique properties, are practically not found in traditional processed cheese chunks. Quercetin is most commonly found in plant flavonoids. Most studies have confirmed the following basic biological properties of quercetin: immunostimulating effect (increases the activity of phagocytes, T- and B-lymphocytes; increases the production of antibodies, reduces the manifestations of secondary immunodeficiency, the incidence of viral infections); oncoprotective effect due to a decrease in the damaging effect of oxygen radicals on the genetic apparatus; antioxidant protection; positive effect in cardiovascular diseases, etc. The cheapest, most bioavailable and frequently used plant raw materials are onions, which also contain bioflavonoids. The article explores the use of wild onions in the creation of functional processed cheese. In connection with the spread of coronavirus infection, it is necessary to strengthen the body's immunity with the help of nutrition. The experiments carried out have established the quantitative presence of flavonoids, vitamin K in processed cheese with wild onions. Inulin and saponins were found in the composition of wild onions, which also proves the advisability of using wild onions in food. The research results on the development of a technology for a new processed cheese and a method of adding wild onion filler in different variations: fresh and in the form of a powder are presented. It was found that fresh addition of Allium odorum imparts a sharp onion aroma, and when dried it imparts a slightly chalky aroma to the final product. The positive effect of the vegetable filler on the shelf life of processed cheese has been proven.