Effects of thermally treated mulberry leaves on the quality, properties, and antioxidant activities of yogurt

Antioxidant, enzymes inhibitory, physicochemical and sensory properties of instant bio-yoghurts containing multi-purpose natural additives

This study aimed to assess the antioxidant, enzyme inhibitory, physicochemical and sensory properties of instant bio-yoghurts containing multi-purpose natural additives. Multi-purpose natural additives were formulated with three natural additives (sweet detar seed, ginger rhizome, and hibiscus calyx flours, as a thickener, flavourant and colourant, respectively) blends at proportions derived from the Design Expert. The additives' synthetic counterparts were formulated with sodium carboxymethylcellulose, vanilla flavor, and red colourant at the same proportions. After that, yoghurt was produced and the additives blends were incorporated into it either in aqueous extract or flour form, yielding bio-yoghurts designated multi-purpose natural additive extract-containing yoghurt (MNAE-yoghurt), multi-purpose natural additive flour-added yoghurt (MNAF-yoghurt), and their multi-purpose synthetic additives-containing counterparts (MSAE-yoghurt and MSAF-yoghurt). A commercially-available bio-yoghurt served as a control. All the yoghurts were lyophilized to obtain instant bio-yoghurts. Subsequently, bioactive components (total phenolics, tannins, total flavonoids and saponins), antioxidants and enzymes [alpha-amylase, alpha-glucosidase, pancreatic lipase, and angiotensin 1-converting enzyme (ACE)] inhibitory activities, as well as proximate, physicochemical and sensory qualities of the bio-yoghurts were determined. The MNAE-yoghurt and MNAF-yoghurt had higher bioactive constituents, total titratable acid levels, and more potent antioxidant and enzyme inhibitory properties, but a lower pH than their synthetic counterparts and the control. The total phenolics, tannins, total flavonoids and saponins levels of MNAE-yoghurt and MNAF-yoghurt were 14.40 ± 0.24 and 16.54 ± 0.62 mg/g, 1.65 ± 0.04 and 1.74 ± 0.08 mg/g, 4.25 ± 0.03 and 4.40 ± 0.02 mg/g, 0.64 ± 0.01 and 0.66 ± 0.02 mg/g, respectively. Among the natural multi-purpose additives-containing bio-yoghurts, MNAF-yoghurt had higher bioactive constituents and stronger antioxidant and enzymes inhibitory properties. Its α-amylase, α-glucosidase, ACE, and pancreatic lipase IC50 values were 72.47 ± 0.47, 74.07 ± 0.02, 25.58 ± 2.58, and 33.56 ± 29.66 μg/mL, respectively. In contrast, MNAE-yoghurt had the highest protein (13.70 ± 0.85%) and the lowest fat (2.63 ± 0.71%) contents. The sensory attributes of all the bio-yoghurts fell within an acceptable likeness range. Overall, the inclusion of multi-purpose natural additives blends enhanced the instant bio-yoghurts' nutritional, health-promoting, and sensory qualities.

Extraction of functional natural products employing microwave-assisted aqueous two-phase system: application to anthocyanins extraction from mulberry fruits

Aqueous two-phase extraction (ATPE) has been extensively utilized for the extraction and separation of tiny-molecule substances as a new system (system with short-chain ethanol and inorganic salts). In this study, an innovative method of extracting anthocyanins from mulberry was developed, employing microwave-assisted extraction with ethanol/ammonium sulfate as a biphasic extractant. Response surface methodology (RSM) was utilized to optimize anthocyanin extraction conditions: 39% ethanol (w/w), 13% ammonium sulfate (w/w), and liquid-to-solid ratio of 45:1, microwave duration 3 min, microwave temperature 32 °C, and microwave power 480 Watt (W). High-performance liquid chromatography (HPLC) analysis demonstrated no significant differences in the structure of mulberry anthocyanins before and after MAATPE treatment, furthermore. The extraction behavior of MAATPE was due to hydrogen bonding, according to Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy analysis found that MAATPE damaged the cell structure via a microwave enhancement effect, which was more favorable to anthocyanin dissolution than standard extraction methods. The DPPH free radical scavenging rate of mulberry extracts at 0.5 mg/mL was higher than that of vitamin C (96.4 ± 0.76%), and the ABTS free radical scavenging rate (82.52 ± 2.13%) was close to that of vitamin C, indicating that MAATPE-derived mulberry extracts have good antioxidant activity.

Yogurt-like product from lupine (Lupinus albus L.) milk as an alternative to dairy products

Recently, the number of people suffering from allergy to caw’s milk has increased. Lupine, a plant rich in protein, can be a good alternative product for non-dairy products production. We aimed to obtain a yogurt-like product based on lupine milk and evaluate its properties. Lupine milk was obtained from lupine seeds, egg white protein powder, disaccharides, and starter cultures were added to the milk to obtain yogurt-like products: samples with maltose, samples with lactose, and samples without sugars. Physico-chemical and microbiological characteristics of the products were determined by the standard techniques. Sensory attributes were evaluated by trained panelists. In the study, the effects of egg white protein powder and disaccharides on the activities of starter cultures and the properties of the yogurt-like products obtained were investigated. The relationship between the addition of sugar and the growth of starter cultures was found to be significant (P < 0.05). In terms of physico-chemical, rheological, and microbiological properties, the yogurt-like products obtained from lupine milk with disaccharides demonstrated good results, especially the sample with maltose. Sensory analysis revealed high sensory properties of the yogurt-like products. Yogurt-like products from lupine milk can be used as an alternative to cow’s milk fermented products, but more detailed studies should be conducted on their formulations.

Studies on Proximate Composition, Mineral and Total Phenolic Content of Yogurt Bites Enriched with Different Plant Raw Material

Yogurt products are consumed by millions of people every day. Consumers’ priority for ready-to-eat yogurt snacks enriched with various plant raw materials have increased each year. Therefore, the aim of this study was to prepare freeze-dried yoghurt bites with the addition of powders of beetroot, mulberry leaves, nettle leaves and rosehip fruit and to investigate these raw materials’ influence on the proximate composition, mineral and total phenolic content. The moisture, protein, fat, carbohydrate and sugar content of the yogurt bites were established using standard methods: mineral composition—using an inductively coupled plasma mass spectrometer (ICP-MS); total phenolic content—by the spectrophotometric method. The results demonstrated that the addition of different raw material powders to the formulation of yogurt bites had no significant influence on carbohydrate, protein and total fat amounts. However, the incorporation of powders of beetroot, mulberry leaves, nettle leaves and rosehip fruit in yogurt bites allowed a significant increase of the amounts of all investigated minerals and total phenolic content of the manufactured bites. Among all investigated yogurt bites, the highest amounts of K, P, Mg, Fe and Zn were determined for yogurt bites enriched with nettle leaves. In conclusion, the enrichment of yogurt bites with freeze-dried plant raw material powders can increase amounts of selected minerals and total phenolic content.