Shanghai Baosheng Electronic Tongue Helps Zou Liqiang's Team at Nanchang University Publish Article

1. Research Background

In the fields of food science and nutrition, peptides have attracted much attention due to their various beneficial physiological functions for the human body. However, many peptides are limited in their wide application in the food industry due to their poor flavor characteristics, especially bitterness. In addition, peptides are prone to degradation in the gastrointestinal environment, leading to a decrease in their biological activity, further limiting their potential use in nutritional supplements and functional foods. To address these issues, researchers have been exploring effective methods to mask the bitterness of peptides and improve their gastrointestinal stability. In recent years, food microcapsule technology has received widespread attention due to its ability to protect sensitive ingredients from external environmental influences and control their release rate and location. Among many microencapsulation technologies, oil in water high internal phase lotion (W/O HIPEs) have become a research hotspot because of their du special structure and functional characteristics. W/O HIPEs are lotion formed by a large number of water droplets dispersed in the continuous oil phase, whose internal water phase volume fraction usually exceeds 74%, thus forming a high internal phase structure. This special structure endows W/O HIPEs with a high specific surface area and a large number of interface regions, providing a good platform for embedding and stabilizing various hydrophilic components. Zou Liqiang's team from Nanchang University published an article on the journal Food Chemistry (IF=8.8) entitled "Encapsulation of bit peptides in water oil high internal phase emulsions reduce their bitterness and improve gastrointestinal stability" (DOI: 10.1016/j.foodchem. 2022.132787). The research of the article aims to use water oil high internal phase lotion to embed bitter peptides to reduce their bitterness and improve gastrointestinal stability. The formation of W/O HIPEs was confirmed by electron microscopy and fluorescence confocal microscopy. High concentration of bitter peptide increased the viscosity, shear modulus and sedimentation stability of lotion, and improved its antioxidant stability. Electronic tongue and sensory analysis showed that peptides encapsulated in HIPEs significantly reduced their bitterness. In addition, simulated gastrointestinal studies have shown that W/O HIPEs can protect the release of peptides in the stomach. The research results indicate that W/O HIPEs can be used to mask the bitterness of peptides and improve their gastrointestinal stability in food, thereby increasing their application as bioactive ingredients in food. The instrument used in this article to measure the bitterness characteristics of bitter peptides embedded in oil-water high internal phase lotion is our electronic tongue of Shanghai Baosheng. What is the specific operation method?

2. Experimental Methods

1. Sample preparation: First, prepare an aqueous phase containing different concentrations of bitter peptides (0, 5, 15, and 30% w/w) dissolved in 5 mM phosphate buffer solution (pH 7.0). In addition, 0.1% w/v azide sodium was added as an antibacterial agent (note: this is a non food grade preservative). Then, a mixture consisting of 1.9 g camellia oil, 1.9 g palm oil, and 0.2 g PGPR was heated in a 70 ℃ water bath for 15 minutes to prepare the oil phase. Then, slowly add 16.0 g of aqueous phase to the heated oil mixture while using a high-speed homogenizer to continuously shear at 8000 rpm for 3 minutes. Then increase the shear rate to 10000 rpm and shear the sample for another minute.

2. Electronic tongue analysis uses electronic tongue (C Tongue, Bosin, China) to determine the flavor characteristics of three different samples: simulated saliva (SSF), 30% bitter peptide solution, and 30% BP-HIPE. Before analysis, dilute 30% BP-HIPE with SSF (1:1 w/w) and stir for 10 minutes to simulate oral processing. Dissolve the bitter peptide in a buffer solution (pH 7.0) to prepare a peptide solution, and dilute it with the same SSF as 30% HIPE. Preheat the instrument for 20 minutes before the experiment, and set the sensor signal amplification factor to 3 times. During analysis, pour 20 mL of the sample into a test beaker and transfer deionized water into another beaker as the cleaning solution. Immerse the sensor array into each sample for 140 seconds three times and monitor the voltage output (mV). Discard the first reading of each sample and analyze using the average voltage reading from the last 20 seconds of the remaining 2 soaking processes.

3. Experimental results

Figure 1: Principal component analysis of simulated saliva ("S"), bitter peptide solution ("B"), and W/O-HIPE ("E") containing 30% bitter peptide using electronic tongue to gain a deeper understanding of HIPE's ability to mask peptide bitterness. This device overcomes some limitations of traditional sensory evaluation methods, such as group subjectivity, fatigue, and inconsistency. Evaluate the effect of encapsulation on bitterness by analyzing three different samples: simulated saliva (SSF), 30% bitter peptide solution, and 30% BP-HIPE. The principal component analysis (PCA) of the data showed that these three samples were separated from each other without crossing (Figure 1), indicating that the electronic tongue can distinguish the taste differences between the samples. Multiple comparative analysis also showed significant taste differences among the three groups (P<0.05). The electronic tongue can clearly distinguish between unencapsulated and encapsulated peptides on the PC1 axis, with a total variance of approximately 97%. However, there was no significant difference between the SSF and BP-HIPE samples, indicating that bitter peptides were not released from the oil droplets in HIPE after dilution.