Evaluation of the functional properties and antidiabetic potential of synbiotic dairy snacks based on Petit Suisse cheese and skyr-like yogurt models

Abstract

Synbiotic dairy products offer stability to functional components with health benefits by modulating the gut microbiota. Type 2 Diabetes Mellitus (T2DM) is the most common form of diabetes, and it is an inflammatory disease associated with gut dysbiosis, hyperglycemia, inflammatory markers, insulin resistance (IR), oxidative stress, hypercholesterolemia, and relative insulin deficiency. In Mexico, it is the second cause of death after cardiovascular diseases. Fermented dairy serves as an effective vehicle for bioactive compounds through gut tract due to the protective properties of food matrix. Some probiotics have demonstrated potential in improving lipid metabolism, such as reducing cholesterol levels and diabetes-related diseases. Based on this information, the objective of this work was to evaluate the functional and antidiabetic properties of two synbiotics dairy models based on a Petit Suisse cheese (PSC) and a skyr-type yogurt (STY) while assessing the impact of adding functional ingredients. Petit Suisse cheese (PSC) is a fresh cheese produced by coagulating milk with rennet, and specific bacteria, or a combination of these elements. Diets that include synbiotic foods with high antioxidant capacity are associated with a reduced risk of diseases such as IR and prediabetes. Blueberries are a rich source of polyphenols and anthocyanins, which are bioactive molecules known for their high antioxidant activity. A PSC base was prepared by adding a starter culture (2%), probiotics (0.5-1%), and prebiotic ingredients (1-2%). Three formulations of PSC, namely PSC1 (without blueberry ingredients), PSC2 (with only blueberry syrup), and PSC3 (with blueberry bagasse and syrup), were developed. These formulations were selected for evaluation of their technological profile through physicochemical analysis (pH, titratable acidity, viscosity, syneresis), proximal analysis, and a sensory evaluation involving 100 participants to assess acceptability. Subsequently, the antidiabetic and functional activity of the formulations were determined before and after an in vitro digestion. The antioxidant profile (ABTS, TPC, and TAC), enzymatic assays (α-amylase and α-glucosidase inhibition), and in vitro cellular assays (antioxidant and anti-inflammatory capacity) were conducted. The addition of blueberry-based ingredients was found to enhance the functional and bioactive profile of the PSC formulations, even after digestion. Among the formulations, PSC3 demonstrated the best acceptability, antidiabetic potential, and antioxidant response. It exhibited the highest content of high molecular weight dietary fiber (8.10 ± 0.60 g/100 d.w.). In the ABTS assay, PSC3 showed the highest antioxidant capacity (60.03 ± 1.12 mg ascorbic acid equivalents/100 g d.w.) and TPC (33% higher than the control PSC1) after digestion. Moreover, PSC3 displayed the best antidiabetic potential in terms of α-amylase and α-glucosidase inhibition, with 61% to 75% inhibition in water-soluble (WS) extracts. It also demonstrated the highest antioxidant and anti-inflammatory capacity in in vitro cell models at a concentration of 100 μg/mL. On the other hand, skyr, an Icelandic fermented dairy product, is gaining popularity due to its distinct sensory characteristics and low-fat high-protein content. There is also increasing interest in the health benefits associated with heat-killed bacteria, now referred to as postbiotics. In this study, three strains (Lactiplantibacillus plantarum 299v (LP299V), Lactiplantibacillus plantarum LPK, and Lactobacillus acidophilus 5 (LA5)) were selected based on their antioxidant capacity and potential to reduce cholesterol levels through bile salt hydrolase (BSH) activity. These strains were used in the production of skyr-type yogurt (STY) using skimmed milk, rennet, and inulin. The STY samples included LA5 (S1), LP299V (S2), and LPK (S3). A sensory analysis was conducted by a panel of 100 participants, followed by the evaluation of the bioactive profile and microbiological viability after in vitro digestion. Additionally, a heat treatment was applied to assess the potential of postbiotics (indicated by the addition of "P" to each code name). Besides the same parameters described in PSC, BSH activity, phagocytic activity, and cytokine expression were also evaluated. All STY with probiotic strains showed a better microbiological viability at the end of digestion. For texture, S2 was preferred. The heat treatment did not have a negative effect on the functional and antidiabetic properties of STY; in fact, it improved the antioxidant potential. PS1 exhibited the highest inhibitory activity against α-glucosidase in both extracts (67%), and PS1 and PS3 showed the highest inhibitory activity against α-amylase (58-81% in both extracts). Lastly, S1 exhibited the highest BSH activity (0.24 U/mL). Cellular models supported the antioxidant capacity, anti-inflammatory capacity, and immunomodulatory potential. In conclusion, synbiotic dairy products, such as PS cheese and skyr, offer a promising approach for delivering functional compounds with health benefits. The addition of blueberry ingredients in PS cheese enhances its antioxidant and antidiabetic properties, while skyr fermented with specific probiotic strains demonstrates potential as a functional dairy product for managing cholesterol levels and promoting antidiabetic effects. These findings highlight the importance of gut microbiota modulation and the incorporation of functional ingredients in dairy matrices to enhance their bioactive profiles. Further research is needed to explore the potential health benefits of fermented dairy products in different matrices and to evaluate their effects on various cellular models and signaling pathways of interest. Additionally, investigations into the bioactivity of peptides, inhibition of carbohydrates-hydrolyzing enzymes, and postbiotic components can contribute to a better understanding of the functional potential of these dairy products.