Beeswax is one of the most important products for the well-being of bee colonies. The wax glands of young worker bees produce beeswax, which serves as a building material for honeycomb construction. Beekeepers using hives with mobile frames mainly utilize local beeswax to make foundations. Any paraffin addition represents adulteration, resulting in a high degree of contamination. During the preparation of re-used beeswax, losses during the process may instigate producers to add cheaper, wax-like substances like paraffin and tallow. This article presents a systematic investigation of the quality of beeswax foundation from six major producers in Vojvodina, Serbia, by applying the classic analytical procedure for the determination of selected physicochemical parameters and instrumental gas chromatography coupled with mass spectrometry (GC–MS) and Fourier transform infrared attenuated total reflection (FTIR–ATR) spectroscopy techniques. FTIR–ATR detected possible paraffin and beef tallow in 72 foundation sheet samples. This technique was complemented with GC–MS. This analysis revealed that paraffin content ranged between 19.75 and 85.68%, while no tallow was detected over the two-year period. Two sheets from each manufacturer were placed into wired Langstroth–Ruth frames and placed in beehives. The construction, based on built cells, was monitored every 24 h. Evaluating newly inserted sheets proved that without quality nectar, there is no intensive building, regardless of adulteration.

Watermelon (Citrullus lanatus) is a widely consumed fruit rich in carotenoids, phenolic compounds, vitamins, and other bioactive constituents associated with antioxidant and health-promoting properties. The present study aimed to develop novel low-sugar watermelon jelly formulations enriched with pectin and single-cell protein (SCP), and to evaluate their bioactive and functional properties, including the antioxidant and enzyme inhibitory activities of their 70% ethanol (70% EtOH) extracts. Six jelly formulations (W1–W6) differing in pectin and SCP supplementation were prepared using concentrated watermelon pulp processed under low-temperature vacuum conditions to preserve thermolabile bioactive compounds. The total phenolic content (TPC) and total flavonoid content (TFC) were determined in the 70% EtOH extracts using spectrophotometric methods. TPC remained relatively stable among the investigated formulations, with the highest value recorded for sample W6, which contained 0.58 g pectin and 0.215 g SCP (1.37 mg gallic acid equivalents (GAE)/mL extract). The highest TFC was observed for sample W5, corresponding to the formulation supplemented with 0.5 g pectin and 0.300 g SCP (5.87 mg quercetin equivalents (QE)/mL extract). Antioxidant activity, evaluated using ABTS, DPPH, and FRAP assays, demonstrated considerable antioxidant potential in all 70% EtOH extracts. The strongest antioxidant activity was observed in pectin-rich samples, with ABTS and FRAP values reaching 89.06 mg Trolox equivalents (TE)/mL extract and 8.99 mg ascorbic acid equivalents (AAE)/mL extract, respectively. The potential carbohydrate-hydrolyzing enzyme inhibitory activity of the 70% EtOH extracts was assessed through α-amylase and α-glucosidase inhibition assays. The formulation containing both pectin and SCP exhibited the strongest α-amylase inhibitory activity (58.93%), whereas the highest α-glucosidase inhibition (60.54%) was observed in the pectin-containing formulation without SCP supplementation. These findings indicate that both pectin and SCP significantly influenced the nutritional and bioactive properties of the developed watermelon jelly formulations. Overall, the results demonstrate that enrichment with pectin and SCP significantly enhances the nutritional and bioactive properties of watermelon jelly formulations. These findings highlight indicate that pectin and SCP were associated with differences in the bioactive and functional properties of the developed watermelon jelly formulations. Overall, the results demonstrate the potential of pectin- and SCP-enriched watermelon jellies as sustainable functional food products with promising antioxidant and enzyme inhibitory properties.