From Medical Herb to Functional Food: Development of a Fermented Milk Containing Silybin and Protein from Milk Thistle

Abstract

Milk thistle is a traditional medicinal herb. Silybin is a medicinal component found in the seed coat of milk thistle, which has liver-protective and anti-cancer properties. Conventional studies have focused on the extraction of silybin with organic reagents, which was inapplicable to the food industry. This study aims to develop a fermented milk containing silybin and protein from the milk thistle seeds. A three step procedure was developed, comprising homogenization of milk thistle seeds, NaHCO3 heat treatment, and microbial fermentation. The silybin was characterized by high performance liquid chromatography, and the protein was quantified and electrophorized. It was found that the homogenization step was essential for the preparation of protein, and the NaHCO3 heat treatment was the crucial step in obtaining silybin. The optimal NaHCO3 treatment settings were 1% NaHCO3, 60°C, and 3 h, and the optimal strains for microbial fermentation were L131 (Rummeliibacillus stabekisii) and RS72 (Lactobacillus plantarum). The silybin yield in the fermented milk reached 11.24–12.14 mg/g seeds, accounting for 72.6–78.4% of the total silybin in the milk thistle seeds, and the protein yield reached 121.8–129.6 mg/g seeds. The fermented milk had a slightly sweet yoghurt-like flavor and could be used as a dietary supplement for silybin and protein.

Use of Directed Lactic Fermentation to Obtain Plant-Based, Upcycled Beverage from Milk Thistle Endosperm

“…This fact may result from the conditions under which the protein extraction from the MTE was carried out (water as an extractant, the pH of the solution, the short extraction time, and the relatively low temperature) and the specificity of the LAB strain used. As shown in the experiment in [26], the extraction efficiency of silybin in fermented milk from milk thistle seeds was 11.24-12.14 mg/g of seeds, which accounted for 72.6-78.4% of the total silybin in S. marianum seeds, with a soluble protein yield reaching 33.8-39.0% of the total protein in seeds. These authors demonstrated that a NaHCO 3 heat treatment was crucial in obtaining silybin.…”

“…Its applications include alleviating antibiotic-associated diarrhea, treating inflammationassociated diseases, and enhancing cholesterol efflux [25]. So far, only one publication describes the use of L. rhamnosus CCTCC M2021577 for the fermentation of extract from milk thistle fruits [26]. Generally, there is a lack of information in the literature on the possibility of processing this plant to obtain alternative protein preparations, fermented and unfermented beverages, and other products from the novel food category, even though milk thistle is a valuable source of nutrients, especially protein.…”

Milk Thistle (Silybum marianum (L.) Gaertner) Endosperm as an Alternative Protein Source for a Sustainable Food System (SFS)—Pilot Studies

“…It is a starting point for the search for new applications of S. marianum, e.g., the production of alternative proteins, plant milk substitutes, or fermented beverages. According to own research [28] and other authors' experiences [85], milk thistle protein extract is a good nutrient for lactic acid bacteria, allowing it to produce innovative milk yogurt substitutes. In the future, however, research on the multidirectional assessment of the allergenicity of milk thistle proteins, their cytotoxicity, and their digestibility, e.g., after the lactic fermentation process should be intensified, which would allow supplementing the existing knowledge about milk thistle and the possibility of its use for a sustainable food system.…”

Use of thistle seeds of modified composition in chocolate mass technology

“…Milk thistle belongs to nutraceuticals, which are used for therapeutic and preventive nutrition. In addition, the seeds are used as an ingredient in health products [5].…”