Lycium barbarum, a homology of medicine and food, contains many active ingredients including polysaccharides, polyphenol, betaine, and carotenoids, which has health benefits and economic value. The bioactive components in Lycium barbarum exhibit the effects of antioxidation, immune regulation, hypoglycemic effects, and vision improvement. Recently, the development of nutrition and health products of Lycium barbarum has been paid more and more attention with the increase in health awareness. A variety of nutrients and bioactive components in wolfberry can be retained or increased using modern fermentation technology. Through fermentation, the products have better flavor and health function, which better meet the needs of market diversification. The main products related to wolfberry fermentation include wolfberry fruit wine, wolfberry fruit vinegar, and lactic acid fermented beverage. In this review, the mainly bioactive components of Lycium barbarum and its deep-processing products of fermentation were summarized and compared. It will provide reference for the research and development of fermented and healthy products of Lycium barbarum.

Wolfberry (Lycium barbarum L.) as a functional food is rich in nutrients and bioactive substances. However, the fresh wolfberry is difficult to preserve, and its deep-processing products are required to improve. In the present study, single-strain fermentation vinegar (SFV) and mixed-strain fermentation vinegar (MFV) were prepared, and the physicochemical, bioactive compounds, antioxidant capacities and volatile characteristics were examined to obtain an optimal method. The results showed that reducing sugar was sufficiently utilized during mixed-strain fermentation, and more acid substances were produced compared with single-strain fermentation. Meanwhile, total phenols content (2.64 ± 0.04 mg GAE/mL), total flavonoids content (1.81 ± 0.01 mg GAE/mL) and antioxidant activities in MFV were significantly increased compared with those in SFV. Rutin, p-hydroxycinnamic acid, and 4-hydroxybenzoic acid presented higher contents in MFV than those in SFV. The contents of total organic acids (88.13 ± 0.13 mg/mL) and total amino acids (6.50 ± 0.17 mg/mL) in MFV were significantly improved compared with those in SFV. Proline, alanine and serine were the top three amino acids in MFV. Moreover, acids, eaters, and alcohols were the pre-dominant volatile organic compounds in MFV, which were higher 9.49%, 55.27%, 18.72% in MFV than those in SFV, respectively. The results suggest that MFV efficiently enhances potential health benefits and flavor, which increases the economic value of wolfberry.

Wolfberry (Lycium barbarum L.), as a kind of combination of medicine and food, is rich in antioxidant components. However, the deep-processed products of wolfberry need to be developed to improve its added value. This study aimed to investigate the nutrients, active antioxidant ingredients, and liver-protective mechanism of mixed-culture fermented wolfberry vinegar (MFV). The results showed that MFV had significantly higher protein and significantly lower fat content than wolfberry juice before fermentation, indicating that MFV was a healthy product. The active ingredient content, which included total phenolics, total flavonoids, polysaccharides, betaine, and antioxidant activities, was significantly increased in MFV after mixed-culture fermentation. Moreover, MFV improved histopathological changes and reduced liver biochemical indicators in alcohol-treated mice, indicating the improvement of liver function. In addition, MFV effectively alleviated alcohol-induced liver injury by increasing the expression of alcohol metabolizing enzymes and inhibiting CYP2E1 activity. MFV regulated the equilibrium between pro-oxidant and antioxidant levels by downregulating pro-oxidant markers and upregulating antioxidant markers. Furthermore, MFV reduced the levels of inflammatory indexes by inhibiting the PI3K/Akt/NF-κB signaling pathway. These results suggest that MFV is a healthy food for liver protection, which provides a strategy for deep-processed products of wolfberry.

There is currently a need for high-value applications of vinegar residue, a major byproduct generated during vinegar production, in order to benefit the environment and economic development. Melanoidins exist in vinegar residue as brown and bioactive macromolecules which are produced during the vinegar brewing process. However, the physicochemical characteristics and potential immunomodulatory activity of melanoidins from vinegar residue (VRM) have yet to be clarified. In this study, VRM exhibited structural heterogeneity, with a molecular weight of 9005.42 Da. Carbohydrates were the dominant component, accounting for 57.86 ± 3.36% (w/w), and xylose was the primary monosaccharide, with molar ratios of 53.15%. In addition, microstructural observations showed clear edges and a relatively smooth surface in VRM samples. Spectral analysis with FTIR showed that VRM has broad-spectrum ultraviolet absorption capacity and contains hydroxyl groups and unsaturated structures. Meanwhile, VRM exhibited higher antioxidant capacity than vinegar melanoidins according to ABTS and FRAP. Furthermore, the effects of VRM on immunomodulation were investigated in macrophages. VRM significantly induced phagocytic capacity and the secretion of NO, TNF-α, and IL-6. VRM at 800 ug/mL effectively exerted an immunomodulatory effect, which was associated with the TLR4-mediated NF-κB pathway. These findings demonstrate that VRM has a polysaccharide skeleton cross-linked with proteins and polyphenols, and possesses antioxidant and immunomodulatory properties. It will provide a novel and functional product for the efficient utilization of vinegar residue.