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Abstract Stingless bees (SLB) are insects bread many centuries ago by indigenous people and more than 500 species have already been described. Interest in SLB's propolis has grown as a way to value and preserve native bees, in addition to investigating/prospecting compounds with biological functionality (antimicrobial activity, antioxidant, etc.). The natural active compounds found in propolis come from different plant sources, and consequently, each propolis may show unique biological/pharmacological activity. There is still an important gap about the profile of chemical compounds, biological and pharmacological potential of propolis produced by SLBs. This work aimed to investigate the presence of phenolic and coumaric compounds (HPLC–DAD-FLD) and the antimicrobial activity (microdilution method) of propolis extracts from five different species of SLB reared in different places. The samples from Melipona quadrifasciata (82.05 mgGAEg−1) and one from, Frieseomelitta doederleini (56.22 mgGAEg−1) showed the highest concentrations of phenolic compounds. It was possible to identify in the propolis samples formononetin, kaempferol, gallic acid and coumarin. Resveratrol was detected in all samples, an unprecedent fact for SLB propolis. Candida albicans was susceptible to all tested extracts, while Escherichia coli was inhibited only by propolis from Melipona quadrifasciata; Enterococcus faecalis was inhibited by propolis from Plebeia droryana., Melipona quadrifasciata and Frieseomelitta doederleini. It was verified that SLB propolis constitutes a source of different biocompounds, which varies according to the location where the bees are raised, and has mainly antifungal activity, generating possibilities of its use in different biotechnological products. Graphical Abstract

There is a scarcity of studies evaluating the influence of different commonly marketed sugars in water kefir beverage production. Therefore, this study aimed to evaluate the fermentation of water kefir grains in different sugary solutions: brown, demerara, refined, coconut, and cane molasses. A total of 10% of each type of sugar was dissolved in sterile water to which 10% of kefir grains were then added and fermented for 48 h at room temperature. Analyses of pH/acidity, soluble solids, lactic/acetic acids, and lactic acid bacteria and yeast counts were performed, in addition to grain weighing at 0 h, 24 h, and 48 h. The microbial biodiversity was measured using PCR-DGGE and DNA sequencing at the species level. A sensory acceptance test was performed on all beverages. Lactobacillus, Lacticaseibacillus, Lentilactobacillus Lactococcus, Leuconostoc, Acetobacter, Saccharomyces, Kluyveromyces, Lachancea, and Kazachstania were present in the kefir grains and the beverages. Molasses showed a more intense fermentation, with greater production of organic acids and higher lactic/acetic acid bacteria and yeast counts (7.46 and 7.49 log CFU/mL, respectively). Refined sugar fermentation had a lower microbial yield of lactic/acetic acid bacteria (6.87 log CFU/mL). Smith’s salience index indicates that the brown-sugar kefir beverage was better accepted among the tasters. The results indicate that the use of alternative sources of sugar to produce water kefir beverages is satisfactory. This opens up new perspectives for the application of kefir microorganisms in the development of beverages with probiotic and functional properties.

The demand for bee products has been growing, especially regarding their application in complementary medicine. Apis mellifera bees using Baccharis dracunculifolia D.C. (Asteraceae) as substrate produce green propolis. Among the examples of bioactivity of this matrix are antioxidant, antimicrobial, and antiviral actions. This work aimed to verify the impact of the experimental conditions applied in low- and high-pressure extractions of green propolis, using sonication (60 kHz) as pretreatment to determine the antioxidant profile in the extracts. Total flavonoid content (18.82 ± 1.15–50.47 ± 0.77 mgQE·g−1), total phenolic compounds (194.12 ± 3.40–439.05 ± 0.90 mgGAE·g−1) and antioxidant capacity by DPPH (33.86 ± 1.99–201.29 ± 0.31 µg·mL−1) of the twelve green propolis extracts were determined. By means of HPLC-DAD, it was possible to quantify nine of the fifteen compounds analyzed. The results highlighted formononetin (4.76 ± 0.16–14.80 ± 0.02 mg·g−1) and p-coumaric acid (−1) as majority compounds in the extracts. Based on the principal component analysis, it was possible to conclude that higher temperatures favored the release of antioxidant compounds; in contrast, they decreased the flavonoid content. Thus, the obtained results showed that samples pretreated with 50 °C associated with ultrasound displayed a better performance, which may support the elucidation of the use of these conditions.

The use of non-dairy matrices for probiotic delivery can be beneficial for vegetarian, vegan and lactose intolerant consumers. Stevia rebaudiana extract can be used as sweetener to replace sucrose for glucose intolerants. This research evaluated the use of kefir grains to prepare a low-calorie, fruit-based kefir beverage. Fermentation was carried out by inoculating kefir grains into a mixture of mango and umbu pulps. Two beverages, one containing sucrose, and the other, stevia, were characterized according to their proximate composition and submitted to a 30-day shelf-life period at 5°C, evaluating lactic acid bacteria, yeasts, pH, acidity, color parameters, soluble solids, ascorbic acid, sensory acceptance, and purchase intention every 10 days. Lactic and acetic acids were analyzed at the beginning and end of the shelf-life. Both beverages showed probiotic potential. The stevia-sweetened beverage had lower calorie content and good sensory acceptance. These results support the possibility to develop low-calorie, fruit-based kefir beverages.

Edible insects are a potential alternative food source of high feed conversion efficiency and protein content. Zophobas atratus is an edible insect that adapts to different diets, enabling sustainable rearing by adding value to by-products and agro-industrial residues. This study aimed to evaluate the performance and nutritional characterization of Zophobas atratus larvae fed with different proportions of grape residue. Physicochemical analysis of the diets and larvae (AOAC procedures), fatty acid profile (chromatographic techniques), metals and non-metals (inductively coupled plasma optical emission spectrometry), larval mass gain, feed conversion efficiency, and mortality rate were assessed. The replacement of 25% of the conventional diet with grape residue increased lipid, ash, and fiber contents and reduced protein, carbohydrates, and energy. It promoted greater mass gain, lower mortality rate, and reduced larval growth time by 51%. Among the replacements, 25% resulted in the second-highest content of calcium, sodium, magnesium, and zinc, and the lowest content of potassium and phosphorus in the larvae. The 100% replacement resulted in the highest amounts of C18:2n6 (27.8%), C18:3n3 (2.2%), and PUFA (30.0%). Replacing 25% of the conventional diet with grape residue is equivalent to the conventional diet in many aspects and improves several larvae performance indices and nutritional values.

In this study, we evaluated the effects of ultrasound-assisted extraction (UAE) under different time-temperature conditions on the content of bioactive compounds, antioxidant and antimicrobial activities of Syrah grape skin residue. The application of UAE showed a positive effect on the extraction of total flavonoids, and a negative effect on total polyphenols. The temperature of 40 °C and 60 °C without the UAE caused an increase of 260% and 287% of the total polyphenols, respectively. Nineteen individually bioactive compounds were quantified. The anthocyanin concentration (malvidin-3,5-di-O-glucoside 118.8–324.5 mg/100 g) showed high variation, to a lesser extent for phenolic acids, flavonoids, flavonols, procyanidins and stilbenes due to the UAE process. The Syrah grape skin residue has a high concentration of total phenolic compounds of 196–733.7 mg·GAE/100 g and a total flavonoid content of 9.8–40.0 mg·QE/100 g. The results of free radical scavenging activity (16.0–48.7 mg/100 mL, as EC50) and its inhibition of microbial growth (0.16 mg/mL, as EC50 for S. aureus, and 0.04 mg/mL, as EC50 for E. coli) by grape skin extract (UAE 40:20) indicate high antioxidant and antibacterial activity. It was concluded that the use of ultrasound needs further analysis for its application in this context, as it has shown deleterious effects on some compounds of interest. Syrah grape skin residue has potential as a source of bioactive antioxidants, antimicrobial activity and for use as a functional food ingredient.