Comparison of prediction models for soy protein isolate hydrolysates bitterness built using sensory, spectrofluorometric and chromatographic data from varying enzymes and degree of hydrolysis.

The bitterness of soy protein isolate hydrolysates prepared using five proteases at varying degree of hydrolysis (DH) and its relation to physicochemical properties, i.e., surface hydrophobicity (H0), relative hydrophobicity (RH), and molecular weight (MW), were studied and developed for predictive modelling using machine learning. Bitter scores were collected from sensory analysis and assigned as the target, while the physicochemical properties were assigned as the features. The modelling involved data pre-processing with local outlier factor; model development with support vector machine, linear regression, adaptive boosting, and K-nearest neighbors algorithms; and performance evaluation by 10-fold stratified cross-validation. The results indicated that alcalase hydrolysates were the most bitter, followed by protamex, flavorzyme, papain, and bromelain. Distinctive correlation results were found among the physicochemical properties, influenced by the disparity of each protease. Among the features, the combination of RH-MW fitted various classification models and resulted in the best prediction performance.

Chinese Propolis: Ultrasound-assisted enhanced ethanolic extraction, volatile components analysis, antioxidant and antibacterial activity comparison.

This study was aimed to enhance the extraction yield of propolis samples using ultrasound technology, analyze the volatile compounds, and compare the antioxidant and antimicrobial effect of propolis extracts of different areas. Four propolis samples were collected from different regions of China, namely: Linqing, Shandong Province (LSP); Yingchun, Heilongjiang Province (YHP); Changge, Henan Province (CHP); and Raohe, Heilongjiang Province (RHP). The ultrasound extracts of CHP and RHP showed a higher total phenolic content (TPC) of 201.78 ± 4.60 mgGAE/g and 166.071 ± 1.53 mgGAE/g, total flavonoid content (TFC) of 519.77 ± 29.90 and 341.227 ± 10.82 mg quercetin/g respectively, as well as high antioxidant and antibacterial activity. Conventional extraction showed 15%-20% lower yield for TPC ranging from 72.02 ± 1.99 to 155.95 ± 3.69 mg GAE/g, TFC ranges from 129.675 ± 6.82 to 412.83 ± 12.14 mg quercetin/g, with lower antibacterial activity. The antioxidant activity of propolis extracts was determined by assays of reducing power, DPPH*, FRAP*, TEAC*, hydroxyl radical scavenging activity and superoxide anion scavenging activity. Collectively, the antioxidant activities of extracts from CHP and RHP were higher than those of the other two extracts(YHP and LSP). All the extracts showed high antimicrobial activity on Staphylococcus aureus, Listeria monocytogenes, and Bacillus subtilis, but no effect on Escherichia coli. A total of 150 compounds in propolis were detected by GC/MS. Terpenes (RHP 34%, YHP 5%, LSP 18%, and CHP 12%) and alcohols (RHP 12%, YHP 13%, LSP 12%, and CHP 10%) showed the highest relative content among all other extracts.

Antiproliferative effects of mealworm larvae (Tenebrio molitor) aqueous extract on human colorectal adenocarcinoma (Caco-2) and hepatocellular carcinoma (HepG2) cancer cell lines.

Recently, insects have aroused the interest of researchers as potential therapeutic resources against malignant diseases such as cancer. In this study, the effects of aqueous extracts from mysore thorn borer (MTB) (Anoplophora chinensis) and mealworm larvae (MWL) (Tenebrio molitor) against cancer cells were investigated. MWL aqueous extract showed higher antiproliferative effects against Caco-2 and HepG2 cells compared to MTB. The IC50 (48 hr) of MWL aqueous extract were 11.44 and 20 mg/ml for Caco-2 and HepG2 respectively. Flow cytometry analysis showed that MWL aqueous extract induced apoptosis in Caco-2 and HepG2 increasing from 2.06% to 74.34% and from 0.04% to 42.14% after 24 hr respectively. Caspase activity assay showed that apoptosis was mediated via death receptor pathway mediated by caspase-8 and -9 followed by the activation of caspase-3; caspase-3 may have induced DNA damage and cell death. These effects may be correlated to its free amino acids. The results of this study demonstrate the potentials of MWL in the development of natural anticancer therapeutics in the future. PRACTICAL APPLICATIONS: Natural nutraceuticals from insects might be useful for the treatment and prevention of cancers such as colorectal and liver cancer. In recent years, edible insects have caught the attention of researchers, because of their potential as an alternative source of food and nutraceuticals. The results of our study showed that MWL extract might provide important anticancer compounds against colon and liver cancer.

In situ monitoring of grape seed protein hydrolysis by Raman spectroscopy.

Raman spectroscopy was used to monitor the enzymatic hydrolysis process of grape seed protein. The degree of hydrolysis (DH), IC50 of the ACE inhibitory activity, and peptide content of the digestive products of grape seed protein were analyzed offline. The partial least squares (PLS), interval partial least squares (IPLS), and joint interval partial least squares (Si-PLS) models of DH, IC50 , and peptide content were established and the optimal pretreatment method was selected. In the optimal model, the corrected model r of the grape seed protein hydrolysis degree is 0.997, the Root Mean Square Error of Cross Validation (RMSECV) is 0.507%. The predicted model r value is 0.9932, the Root Mean Square Error of Prediction (RMSEP) is 1.15%. The corrected model r value of the IC50 is 0.9965, the RMSECV is 11.9%. The r value and RMSEP of predicted model are 0.9978 and 9.64%. The corrected model r value of the peptide content is 0.9955, the RMSECV is 12.7%, the predicted model r value is 0.9953, and the RMSEP is 15.4%. These results showed that in situ real-time monitoring of grape seed protein hydrolysis process can be achieved by Raman spectroscopy. PRACTICAL APPLICATIONS: This study uses Raman spectroscopy method to establish the quantification of proteolysis, IC50, and peptide content of the simulated digestive products during grape seed proteolysis. Analyze the model to monitor and evaluate the target parameters during the entire grape seed proteolysis process. In situ real-time monitoring of grape seed proteolysis is of great significance to the entire grape seed active peptide industry.

Comparison of the nutritional value of mysore thorn borer (Anoplophora chinensis) and mealworm larva (Tenebrio molitor): Amino acid, fatty acid, and element profiles.

There is increasing interest in using insects as an alternative nutrient source and Mysore thorn borer (MTB) (Anoplophora chinensis) might have nutritional and functional relevance for humans. The nutritional composition of MTB (amino acids, fatty acids, and elements profiles) was examined and compared with mealworm larva (MWL) (Tenebrio molitor). MTB was found to contain 19 amino acids, including all essential amino acids. A total of 16 fatty acids were detected including polyunsaturated fatty acids (e.g. α-linolenic acid and linoleic acid). Moreover, MTB had a low n - 6/n - 3 ratio and contained some essential elements, such as iron, zinc, calcium, and potassium. These results demonstrated that MTB might be a potential source of nutritional compounds for human consumption.

Caspase 3-mediated cytotoxicity of mealworm larvae (Tenebrio molitor) oil extract against human hepatocellular carcinoma and colorectal adenocarcinoma.

ETHNOPHARMACOLOGICAL RELEVANCE: Mealworm larvae (MWL) (Tenebrio molitor) have been traditionally used in Asian countries for the treatment of liver diseases, including cancer. However, to date, there is marginal information on the mechanisms underlying the anticancer activity of MWL oil. AIM OF THE STUDY: This study aims to determine the in vitro effect of MWL oil on human hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (Caco-2) cells growth in order to produce insect-derived chemotherapeutic agents against cancer. MATERIALS AND METHODS: MWL oil was extracted, and its effects on cancer cells growth were investigated, by the MTT reduction, AO/EB staining, Hoechst 33258 nuclear staining, apoptosis, comet, and caspase activity assays. RESULTS: MWL oil inhibited HepG2 and Caco-2 growth, with IC50 (48 h) values of 0.98% for HepG2 and 0.37% for Caco-2 cells. In addition, flow cytometry analysis demonstrated that 24 h-MWL oil treatment increased early and late apoptosis from 0.04% to 39.77% and from 2.06% to 74.34% on HepG2 and Caco-2 cells, respectively. The mechanism of apoptosis was associated with the death receptor pathway by the activation of caspases -8, -9, and -3, and correlated to its fatty acids action. CONCLUSION: Results of this study demonstrated the potential of MWL oil in the development of natural anticancer therapeutic agents.

Effect of alkali concentration on digestibility and absorption characteristics of rice residue protein isolates and lysinoalanine.

The effect of alkali concentration on the digestibility and absorption characteristics of rice residue protein isolates (RPI) and lysinoalanine (LAL) was studied. When NaOH concentration was 0.03 M, the in vitro digestibility of RPI reached a maximum, and when NaOH concentration was higher than 0.03 M, the in vitro digestibility decreased. Alkali treatment reduced the release of all amino acids, especially arginine, lysine, phenylalanine, tyrosine, cysteine, and threonine. LAL only released 2.65-9.28% of the total LAL content, which was mainly combined with longer peptide chains, and the molecular weight was mostly accumulated between 1000 Da and 3000 Da. The experimental model of rats in the small intestine perfusion showed that the high alkali concentration significantly reduced the absorption rate of RPI, and LAL had no specific absorption site in the small intestine of rats, and was not available for intestinal absorption.

Impact of ultrasound pretreatment on hydrolysate and digestion products of grape seed protein.

The effects of ultrasound pretreatment with different working modes, including mono frequency ultrasound (MFU), simultaneous dual frequency ultrasound (SDFU) and alternate dual frequency ultrasound (ADFU) using energy-gather counter flow ultrasound equipment, on the degree of hydrolysis (DH) of grape seed protein (GSP) hydrolysate and IC50 of GSP digestion products were studied. Amino acid composition analysis (AACA), ultraviolet-visible (UV) spectroscopy and atomic force microscopy (AFM) of GSP with different ultrasound pretreatments were measured. The results showed that MFU, SDFU and ADFU pretreatments improved the DH and reduced the IC50 of GSP significantly (P < .05). The MFU of 20 kHz and SDFU of 20/40 kHz showed higher ACE inhibitory activity within the MFU and SDFU groups, respectively. ADFU of 20/35 kHz produced the highest ACE inhibitory activity among the three working modes (MFU, SDFU and ADFU). AACA showed that all the working modes of the ultrasound pretreatment could increase the amount of hydrophobic amino acids and the total amino acids. The changes in UV spectra and amino acid analysis indicated the unfolding of protein structure and exposure of more hydrophobic groups by SDFU and ADFU pretreatments. AFM analysis of the GSP indicated that the microstructures were destroyed and the particle size reduced after dual-frequency ultrasound pretreatments. Therefore, energy-gather counter flow ultrasound pretreatment is an effective method to improve the DH and reducing the IC50 due to the changes of molecular conformation and effects on the microstructure by sonochemistry of GSP. In conclusion, it is necessary to select the frequency and working modes of ultrasound pretreatment for the preparation of ACE inhibitory peptide of GSP.