Evaluation of Radio Frequency-Assisted Enzymatic Extraction of Non-Anthocyanin Polyphenols from Akebia trifoliata Flowers and Their Biological Activities Using UPLC-PDA-TOF-ESI-MS and Chemometrics

Natural pigments: innovative extraction technologies and their potential application in health and food industries

Natural pigments, or natural colorants, are frequently utilized in the food industry due to their diverse functional and nutritional attributes. Beyond their color properties, these pigments possess several biological activities, including antioxidant, anti-inflammatory, anticancer, antibacterial, and neuroprotective effects, as well as benefits for eye health. This review aims to provide a timely overview of the potential of natural pigments in the pharmaceutical, medical, and food industries. Special emphasis is placed on emerging technologies for natural pigment extraction (thermal technologies, non-thermal technologies, and supercritical fluid extraction), their pharmacological effects, and their potential application in intelligent food packaging and as food colorants. Natural pigments show several pharmaceutical prospects. For example, delphinidin (30 µM) significantly inhibited the growth of three cancer cell lines (B16-F10, EO771, and RM1) by at least 90% after 48 h. Furthermore, as an antioxidant agent, fucoxanthin at the highest concentration (50 μg/mL) significantly increased the ratio of glutathione to glutathione disulfide (p < 0.05). In the food industry, natural pigments have been used to improve the nutritional value of food without significantly altering the sensory experience. Moreover, the use of natural pH-sensitive pigments as food freshness indicators in intelligent food packaging is a cutting-edge technological advancement. This innovation could provide useful information to consumers, increase shelf life, and assist in evaluating the quality of packaged food by observing color variations over time. However, the use of natural pigments presents certain challenges, particularly regarding their stability and higher production costs compared to synthetic pigments. This situation underscores the need for further investigation into alternative pigment sources and improved stabilization methods. The instability of these natural pigments emphasizes their tendency to degrade and change color when exposed to various external conditions, including light, oxygen, temperature fluctuations, pH levels, and interactions with other substances in the food matrix.

Impact of salting-in/out assisted extraction on rheological, biological, and digestive, and proteomic properties of Tenebrio molitor larvae protein isolates

In this study, NaCl (salting-in) and (NH4)2SO4 (salting-out) treatments were employed in alkaline extraction and acid precipitation procedures, respectively, to enhance the extraction of Tenebrio molitor larvae protein isolates (TPIs). The in vitro digestibility, rheological properties, biological activities, and proteomic analysis of TPIs were investigated. The results showed that salting-in treatment did not result in significant differences (P > 0.05) in antioxidant activities (except for ABTS radical scavenging), but increased tumor necrosis factor β (TNF-β) and the degree of hydrolysis (DH). Salting-out treatment significantly (P < 0.05) enhanced trichloroacetic acid-soluble peptide yield (Tsp) and ACE inhibitory activities but negatively affected antioxidant and antibacterial activities. The combined salting-in-out treatment produced the highest values of DH (45.80 %), Tsp (72.46 %), and TNF-β (0.86 mg/kg). Proteomic analysis using UPLC-MS/MS identified 141 proteins, including metabolic enzymes and actin, in the TPIs. While the salting treatments did not significantly alter the protein compositions, they primarily affected protein content. Overall, salting-in and salting-out treatments can effectively enhance specific biological properties of T. molitor protein isolates, particularly digestibility and ACE inhibitory activities, while salting-out treatments may reduce antioxidant functions. These findings suggest the potential of salting-assisted extractions for optimizing insect protein functionality in food and nutraceutical applications.