High Hydrostatic Pressure (HHP)-Induced Structural Modification of Patatin and Its Antioxidant Activities

Antioxidant capacity and peptidomic analysis of in vitro digested Camelina sativa L. Crantz and Cynara cardunculus co-products

In recent decades, the food system has been faced with the significant problem of increasing food waste. Therefore, the feed industry, supported by scientific research, is attempting to valorise the use of discarded biomass as co-products for the livestock sector, in line with EU objectives. In parallel, the search for functional products that can ensure animal health and performances is a common fundamental goal for both animal husbandry and feeding. In this context, camelina cake (CAMC), cardoon cake (CC) and cardoon meal (CM), due valuable nutritional profile, represent prospective alternatives. Therefore, the aim of this work was to investigate the antioxidant activity of CAMC, CC and CM following in vitro digestion using 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Total phenolic content (TPC) and angiotensin converting enzyme (ACE) inhibitory activity, actively involved in modulating antioxidant properties, were also studied. Further, a peptidomic analysis was adopted to substantiate the presence of bioactive peptides after in vitro digestion. The results obtained confirmed an interesting nutritional profile of CAMC, CC and CM and relevant antioxidant and ACE inhibitory activities. In particular, considering antioxidant profile, CM and CC revealed a significantly higher (10969.80 ± 18.93 mg TE/100 g and 10451.40 ± 149.17 mg TE/100 g, respectively; p < 0.05) ABTS value than CAMC (9511.18 ± 315.29 mg TE/100 g); a trend also confirmed with the FRAP assay (306.74 ± 5.68 mg FeSO4/100 g; 272.84 ± 11.02 mg FeSO4/100 g; 103.84 ± 3.27 mg FeSO4/100 g, for CC, CM and CAMC, respectively). Similar results were obtained for TPC, demonstrating the involvement of phenols in modulating antioxidant activity. Finally, CAMC was found to have a higher ACE inhibitory activity (40.34 ± 10.11%) than the other matrices. Furthermore, potentially bioactive peptides associated with ACE inhibitory, anti-hypertensive, anti-cancer, antimicrobial, antiviral, antithrombotic, DPP-IV inhibitory and PEP-inhibitory activities were identified in CAMC. This profile was broader than that of CC and CM. The presence of such peptides corroborates the antioxidant and ACE profile of the sample. Although the data obtained report the important antioxidant profile of CAMC, CC, and CM and support their possible use, future investigations, particularly in vivo trials will be critical to evaluate and further investigate their effects on the health and performance of farm animals.

Impacts of sonication and high hydrostatic pressure on the structural and physicochemical properties of quinoa protein isolate dispersions at acidic, neutral and alkaline pHs

Herein, 1 wt% quinoa protein isolate (QPI) was exposed to sonication using a 20 kHz ultrasonicator equipped with a 6 mm horn (14.4 W, 10 mL, up to 15 min) or high hydrostatic pressure (HHP, up to 600 MPa, 15 min) treatments at pH 5, pH 7, and pH 9. The changes to physicochemical properties were probed by SDS-PAGE, FTIR, free sulfhydryl group (SH), surface hydrophobicity (H₀), particle size and solubility. As revealed by SDS-PAGE, substantial amounts of 11S globulin participated in the formations of aggregates via SS bond under HHP, particularly at pH 7 and pH 9. However, protein profiles of QPI were not significantly affected by the sonication. Free SH groups and surface hydrophobicity were increased after the sonication treatment indicating protein unfolding and exposure of the embedded SH and/or hydrophobic groups. An opposite trend was observed in HHP treated samples, implying aggregation and reassociation of structures under HHP. HHP and sonication treatments induced a decrease in ordered secondary structures (random coil and β-turn) accompanied with an increase in disordered secondary structures (α-helix and β-sheet) as probed by FTIR. Finally, the sonication treatment induced a significant improvement in the solubility (up to ∼3 folds at pH 7 and ∼2.6 folds at pH 9) and a reduction in particle sizes (up to ∼3 folds at pH 7 and ∼4.4 folds at pH 9). However, HHP treatment (600 MPa) only slightly increased the solubility (∼1.6 folds at pH 7 and ∼1.2 folds at pH 9) and decreased the particle size (∼1.3 folds at pH 7 and ∼1.2 folds at pH 9). This study provides a direct comparison of the impacts of sonication and HHP treatment on QPI, which will enable to choose the appropriate processing methods to achieve tailored properties of QPI.

Effect of high hydrostatic pressure processing on the structure, functionality, and nutritional properties of food proteins: A review

Proteins are important food ingredients that possess both functional and nutritional properties. High hydrostatic pressure (HHP) is an emerging nonthermal food processing technology that has been subject to great advancements in the last two decades. It is well established that pressure can induce changes in protein folding and oligomerization, and consequently, HHP has the potential to modify the desired protein properties. In this review article, the research progress over the last 15 years regarding the effect of HHP on protein structures, as well as the applications of HHP in modifying protein functionalities (i.e., solubility, water/oil holding capacity, emulsification, foaming and gelation) and nutritional properties (i.e., digestibility and bioactivity) are systematically discussed. Protein unfolding generally occurs during HHP treatment, which can result in increased conformational flexibility and the exposure of interior residues. Through the optimization of HHP and environmental conditions, a balance in protein hydrophobicity and hydrophilicity may be obtained, and therefore, the desired protein functionality can be improved. Moreover, after HHP treatment, there might be greater accessibility of the interior residues to digestive enzymes or the altered conformation of specific active sites, which may lead to modified nutritional properties. However, the practical applications of HHP in developing functional protein ingredients are underutilized and require more research concerning the impact of other food components or additives during HHP treatment. Furthermore, possible negative impacts on nutritional properties of proteins and other compounds must be also considered.

Impact of the Structural Modifications of Potato Protein in the Digestibility Process under Semi-Dynamic Simulated Human Gastrointestinal In Vitro System

The raising consumer demand for plant-derived proteins has led to an increased production of alternative protein ingredients with varying processing histories. In this study, we used a commercially available potato protein ingredient with a nutritionally valuable amino acid profile and high technological functionality to evaluate if the digestibility of a suspension with the same composition is affected by differences in the structure. Four isocaloric (4% protein, w/w) matrices (suspension, gel, foam and heat-set foam) were prepared and their gastrointestinal fate was followed utilizing a semi-dynamic in vitro digestion model. The microstructure was observed by confocal laser scanning microscopy, protein breakdown was tested by electrophoresis and free amino acids after intestinal digestion was estimated using liquid chromatography/triple-quadruple-mass spectrometry (LC-TQMS). The heat-treated samples showed a higher degree of hydrolysis and lower trypsin inhibitory activity than the non-heat-treated samples. An in vitro digestible indispensable amino acid score was calculated based on experimental data, showing a value of 0.9 based on sulfur amino acids/valine as the limiting amino acids. The heated samples also showed a slower gastric emptying rate. The study highlights the effect of the food matrix on the distribution of the peptides created during various stages of gastric emptying.

Yeast-derived potato patatins: Biochemical and biophysical characterization

Potato patatin is considered a valuable plant protein by the food industry for its exceptional functional properties and nutritional value. Nonetheless, it has not been widely used due to its low abundance in potatoes and high cost. Pichia pastoris was utilized for expression of patatin to overcome agricultural limitations. Biochemical and biophysical characterization of Patatin-B2 (rPatB2) and Patatin-17 (rPat17) is described. rPatB2 and rPat17 had higher zeta potential and superior solubility at various pH conditions in comparison with commercial patatin, whereas particle size distribution was similar. Inflection temperatures were higher than potato isolated patatins. Antioxidant capacity of rPatB2 and rPat17 was similar to that of commercial patatin and the specific enzymatic activity of rPatB2 was 5-fold higher than rPat17 and patatins isolated from potato. Results indicate yeast-derived patatin properties are comparable to patatins from potatoes, suggesting their potential use in various plant-based products such as meat and dairy analogues.

Potato protein: An emerging source of high quality and allergy free protein, and its possible future based products

Recently protein has gained eminence due to awareness and demand for healthy food. Potato proteins are extracted from potato fruit juice and industrial potato waste; its nutritional and functional values have been found more significant than other vegetables and cereal proteins. Potato proteins can be easily extracted by various separation techniques, including an ion exchange (IEX) and expanded bed adsorption (EBA), and their functional properties can be modified for desire purposes. It contains many essential amino acids necessary for the human body, with an amino acid score (AAS) of 65%. Recent research on potato proteins resulted in several descriptions of new technologies to produce food-grade potato protein. It has recently drawn more attention as a protein source for human consumption, especially as an allergy free protein source and selective activity against cancer cells. Growing shreds of evidence have highlighted that potato protein can be used in many upcoming nutraceuticals and allergy-free food products. Therefore it is gaining more attention from nutritionists and food scientists. This review has summarized the recent knowledge on the nutritional and functional aspects of potato proteins, especially its non-allergic properties, enhancement in functional properties, and possible future-based products.

Integrated Efforts for the Valorization of Sweet Potato By-Products within a Circular Economy Concept: Biocomposites for Packaging Applications Close the Loop

With the aim to fully exploit the by-products obtained after the industrial extraction of starch from sweet potatoes, a cascading approach was developed to extract high-value molecules, such as proteins and pectins, and to valorize the solid fraction, rich in starch and fibrous components. This fraction was used to prepare new biocomposites designed for food packaging applications. The sweet potato residue was added to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in various amounts up to 40 wt % by melt mixing, without any previous treatment. The composites are semicrystalline materials, characterized by thermal stability up to 260 °C. For the composites containing up to 10 wt % of residue, the tensile strength remains over 30 MPa and the strain stays over 3.2%. A homogeneous dispersion of the sweet potato waste into the bio-polymeric matrix was achieved but, despite the presence of hydrogen bond interactions between the components, a poor interfacial adhesion was detected. Considering the significant percentage of sweet potato waste used, the biocomposites obtained show a low economic and environmental impact, resulting in an interesting bio-alternative to the materials commonly used in the packaging industry. Thus, according to the principles of a circular economy, the preparation of the biocomposites closes the loop of the complete valorization of sweet potato products and by-products.

Physicochemical properties, antioxidant activities, and binding behavior of 3,5-di-O-caffeoylquinic acid with beta-lactoglobulin colloidal particles

Milk proteins and polyphenols are increasingly being studied as functional ingredients due to the epidemiologically-proved health benefits. In this study, composite β-lactoglobulin (β-lg) or β-lactoglobulin nanoparticles (β-lgNPs)-3,5-di-O-caffeoylquinic acid (3,5diCQA) with superior physicochemical and antioxidant activity (AA) were produced using β-lg and 3,5-di-O-caffeoylquinic acid. The main interactions between β-lg or β-lgNPs with 3,5diCQA were hydrogen bonding and hydrophobic effects. The 3,5diCQA caused a decrease in α-helix and β-sheet structure with a corresponding increase in unordered structure. Compared to β-lg alone, composite β-lg or β-lgNPs-3,5diCQA slightly decreased the particle size but increased their negative surface potentials especially for β-lg or β-lgNPs at a molar ratio of 5:1. The addition of 3,5diCQA appreciably improved the AA in a dose-dependent manner. These results shed light on the structural, physicochemical, and AA of composite β-lg or β-lgNPs-3,5diCQA non-covalent complexes, important for application as functional ingredients in food solutions as well as in the pharmaceutical industry.

Effect of thermosonication pre-treatment on mung bean (Vigna radiata) and white kidney bean (Phaseolus vulgaris) proteins: Enzymatic hydrolysis, cholesterol lowering activity and structural characterization

Protein hydrolysates have attained great attention due to a good nutritive food ingredient and higher biological activities. In this study, thermosonication, ultrasound and heat were used as a pre-treatment to obtain (<3KDa) hydrolysate from mung bean and white kidney bean to understand the mechanism of cholesterol absorption into micelle and inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA) activity. Size exclusion high performance liquid chromatography (SE-HPLC) results of mung bean showed that the concentration of peptides (0.5KDa-1KDa and 1-3KDa) in the hydrolysate were significantly (p < 0.05) increased after thermosonication while, the peptides concentration (1-3KDa) in white kidney bean was significantly (p < 0.05) decreased. Thermosonication of mung bean hydrolysate exhibited higher inhibition of cholesterol solubilization, hydrophobicity and antioxidant activities. In addition, there was no difference observed in HMG-CoA activity and hydrophobicity between ultrasound alone and ultrasound combined with heat i.e. thermosonication treated hydrolysate of white kidney bean. Changes in secondary and tertiary structures were also analyzed under different processing conditions with maximum change due to thermosonication. Results indicated that mung bean hydrolysate had a great potential for inhibition of cholesterol synthesis and its solubility in the micelle, antioxidant activity and also convinced for its application in food and nutraceutical industries.

Comparison of Thermal and High-Pressure Gelation of Potato Protein Isolates

Potato protein isolate (PPI), a commercial by-product of the starch industry, is a promising novel protein for food applications with limited information regarding its techno-functionality. This research focused on the formation of both thermal and high-pressure gels at acidic and neutral pH levels. Our results reveal that physical gels are formed after 30 min by heat at pH 7 and pH 3, while pressure (300-500 MPa) allows the formation of physical gels only at pH 3, and only when the system crosses 30 °C by adiabatic heating during pressurization. Texture profile analysis (TPA) revealed that gel hardness increased with both gelation temperature and pressure, while water-holding capacity was lower for the pressure-induced gels. The proteins released in the water-holding test suggested only partial involvement of patatin in the gel formation. Vitamin C as a model for a thermally liable compound verified the expected better conservation of such compounds in a pressure-induced gel compared to a thermal one of similar textural properties, presenting a possible advantage for pressure-induced gelation.

Effect of Chinese Cinnamon Powder on the Quality and Storage Properties of Ground Lamb Meat during Refrigerated Storage

This study was undertaken to evaluate the impact of Chinese cinnamon powder (w/w), at the levels of 0.5%, 1.5%, and 2.5% and control (without additive) on ground lamb meat quality. The samples were stored at 4°C and examined for pH, color, lipid oxidation (thiobarbituric acid reactive substances) and total viable counts (TVC). The results demonstrated that pH values were declined with the increase of Chinese cinnamon levels compared to control group. The L* values throughout the storage were significantly higher (p<0.05) in the control group than in other treatment groups, while a* values were decreased with the increase of Chinese cinnamon levels. The addition of Chinese cinnamon powder strongly inhibited (p<0.05) thiobarbituric acid reactive substances (TBARS) and TVC in all treated samples. It can be concluded that Chinese cinnamon powder in lower concentration 0.5% has the ability to maintain the quality of ground lamb in comparison with other treated samples.

High Hydrostatic Pressure-Assisted Extraction of High-Molecular-Weight Melanoidins from Black Garlic: Composition, Structure, and Bioactive Properties

Melanoidin is one of the most important ingredients in black garlic due to the high nutritional values and biological functions. High hydrostatic pressures from 200 to 500 MPa were employed to extract the melanoidins from black garlic for improving the extraction efficiency and enhancing the activities. The results indicated that total phenolics, flavonoids, and sugar yields were all increased when pressure was applied and the antioxidant and overall reducing power was maximized. The bioactive properties of protein tyrosine phosphatase 1B, angiotensin-converting enzyme, and trypsin inhibitory activities were also enhanced compared with the control. Moreover, FT-IR spectroscopy indicated high pressure altered the melanoidin structures to different degrees. It was found that an application of 300 MPa for 5 min was the optimal treatment protocol under all operating conditions.

High hydrostatic pressure (HHP) effects on antigenicity and structural properties of soybean β-conglycinin

In this study, the effect of high hydrostatic pressure (HHP) on antigenicity, free sulfhydryl group (SH) content, hydrophobicity (Ho), fluorescence intensity and circular dichroism data of soybean β-conglycinin was studied. The antigenicity of soybean β-conglycinin was decreased significantly at pressures 200-400 MPa. The antigenicity inhibition rate of β-conglycinin declined from 92.72 to 55.15%, after being treated at 400 MPa for 15 min. Results indicated that free sulphydryl (SH) groups and surface Ho of β-conglycinin were significantly increased at pressures 200-400 MPa and 5-15 min, whereas these properties decreased at the treatments above 400 MPa and 15 min. The maximum fluorescence intensity was noticed at 400 MPa and 15 min. The circular dichroism data analysis revealed that the amount of β-turns and unordered structure significantly increased, while the content of α-helix1 and β-strand1 noticeably decreased. These results provide evidence that HHP-induced the structural modification of β-conglycinin and could alter the antigenicity of β-conglycinin.