Physicochemical, Digestive, and Sensory Properties of Panax Notoginseng Saponins Encapsulated by Polymerized Whey Protein

Bitter flavors and bitter compounds in foods: identification, perception, and reduction techniques

Bitterness is one of the five basic tastes generally considered undesirable. The widespread presence of bitter compounds can negatively affect the palatability of foods. The classification and sensory evaluation of bitter compounds have been the focus in recent research. However, the rigorous identification of bitter tastes and further studies to effectively mask or remove them have not been thoroughly evaluated. The present paper focuses on identification of bitter compounds in foods, structural-based activation of bitter receptors, and strategies to reduce bitter compounds in foods. It also discusses the roles of metabolomics and virtual screening analysis in bitter taste. The identification of bitter compounds has seen greater success through metabolomics with multivariate statistical analysis compared to conventional chromatography, HPLC, LC-MS, and NMR techniques. However, to avoid false positives, sensory recognition should be combined. Bitter perception involves the structural activation of bitter taste receptors (TAS2Rs). Only 25 human TAS2Rs have been identified as responsible for recognizing numerous bitter compounds, showcasing their high structural diversity to bitter agonists. Thus, reducing bitterness can be achieved through several methods. Traditionally, the removal or degradation of bitter substances has been used for debittering, while the masking of bitterness presents a new effective approach to improving food flavor. Future research in food bitterness should focus on identifying unknown bitter compounds in food, elucidating the mechanisms of activation of different receptors, and developing debittering techniques based on the entire food matrix.

Effects of Panax notoginseng Saponins Encapsulated by Polymerized Whey Protein on the Rheological, Textural and Bitterness Characteristics of Yogurt

Panax notoginseng saponins (PNSs) have been used as a nutritional supplement for many years, but their bitter taste limits their application in food formulations. The effects of PNS (groups B, C, and D contained 0.8, 1.0 and 1.2 mg/mL of free PNS, respectively) or Panax notoginseng saponin-polymerized whey protein (PNS-PWP) nanoparticles (groups E, F, and G contained 26.68, 33.35 and 40.03 mg/mL of PNS-PWP nanoparticles, respectively) on the rheological, textural properties and bitterness of yogurt were investigated. Group G yogurt showed a shorter gelation time (23.53 min), the highest elastic modulus (7135 Pa), higher hardness (506 g), higher apparent viscosity, and the lowest syneresis (6.93%) than other groups, which indicated that the yogurt formed a stronger gel structure. The results of the electronic tongue indicated that the bitterness values of group E (-6.12), F (-6.56), and G (-6.27) yogurts were lower than those of group B (-5.12), C (-4.31), and D (-3.79), respectively, which might be attributed to PNS being encapsulated by PWP. The results indicated that PWP-encapsulated PNS could cover the bitterness of PNS and improve the quality of yogurt containing PNS.