Upcycling and zero-waste food processing are transforming how we think about leftovers from farms, fisheries, and food production. Instead of letting nutrient-rich coproducts go to waste, new sustainable technologies - such as smart fermentation, green extraction methods, and innovative biotransformation - can turn them into valuable ingredients for healthy foods, supplements, and even animal feed. These materials often contain proteins, fibers, beneficial fats, and health-promoting bioactive compounds. By reclaiming them, we not only reduce landfill use and environmental impact but also strengthen food security, support local economies, and move closer to a truly circular food system. This review highlights sustainable strategies for valorizing agricultural, oilseed, and marine coproducts into high-value functional ingredients and industrial materials, thereby advancing the transition toward a zero-waste, circular bioeconomy.

Type 2 diabetes (T2D) is one of the fast growing diet-related chronic diseases throughout the world. Tea contains several bioactive compounds, some of which render health benefits. Black tea polysaccharides (BTPS), extracted from low grade quality tea leaves, after processing, were examined for their in-vitro antidiabetic activities (α-glucosidase inhibitory and glucose uptake activities), chemical compositions (yield, monosaccharides, amino acids, and minerals), and antioxidant activities as well as toxicity (cytotoxicity and genotoxicity). In addition, 50% lethal dose (LD₅₀) for BTPS was determined using an acute toxicity test to assess the safe use of it as a dietary ingredient. BTPS had strong α-glucosidase inhibitory activity with IC₅₀ value of 3.4 µg/mL. This was much lower than that of the positive control, pharmaceutical glucosidase inhibitor acarbose with IC₅₀ of 687.5 μg/mL. BTPS also increased glucose uptake into the adipocyte differentiated 3T3-L1 MBX cells. Neither cytotoxic nor mutagenic effects were found for BTPS. The LD₅₀ of BTPS for acute toxicity demonstrated that it was safe to use. The present work suggests that BTPS can be used as an antidiabetic dietary ingredient without posing any potential health risk.

Cherry laurel (dark purple or black when mature) is a popular summer fruit in the Black Sea region of Turkey. It has been gaining popularity as a valuable source of healthy fruit over the last two decades and is a good source of nutrients and polyphenols together with high antioxidant activity. This contribution discusses nutritional characteristics, antioxidants, polyphenols, and health benefits of cherry laurel. Where available, comparisons are made with other cherry fruits (Cornelian, sweat, and sour) and blueberry. Although several health benefits of this fruit and its seeds have been known as home-made and traditional medicine, in vivo and well-designed human clinical trials are scarce. Therefore, additional carefully-designed human clinical trials are needed to validate the health benefits of this fruit.

Procuring valuable bioactive compounds from low quality green tea is of great interest. Green tea polysaccharides (GTPS), obtained from low quality tea leaves, were examined for their yield, monosaccharide composition, total phenolic content, antioxidant potential, and structures as well as molecular weight distribution and in vitro anti-diabetic activities. GTPS were also evaluated for their toxicity by performing cytotoxicity and genotoxicity. Additionally, 50% lethal dose (LD₅₀) for GTPS was determined using an acute toxicity test to assess the safe use of it as a dietary supplement. Monosaccharides of GTPS were mainly composed of xylose, glucose, ribose, galactose, arabinose, and glucuronic acid. GTPS exhibited 91.86% α-glucosidase inhibition at 0.5 mg/mL concentration. The α-glucosidase inhibitory activity of GTPS was higher than that of pharmacological glucosidase inhibitor, acarbose, which exhibited only 47.86% inhibition at 2.5 mg/mL concentration. Neither cytotoxic nor no mutagenic effects were found for GTPS. The acute toxicity also showed that LD₅₀ of GTPS was greater than 5,000 mg/kg. The present work suggests that GTPS can be considered as an anti-diabetic dietary supplement without posing any potential health risk.