Influence of different organic solvents on the functional and sensory properties of lupin (Lupinus angustifolius L.) proteins

Physico-chemical, functional, and structural properties of un-defatted, cold and hot defatted yellow lupin protein isolates

This study investigates the structure, physico-chemical and functional properties of yellow lupin isolate protein (YLPI) obtained by different processes (conventional wet and purely aqueous fractionation) from un-defatted (YLPIU), and hot (YLPIHD) and cold (YLPICD) defatted flour. The defatting process modified the physical, structural and functional characteristics of lupin protein isolates. Indeed, a decrease of α-helix, free sulfhydryl groups amount and an increase of disulfide bond levels were observed for defatted samples, improving their emulsifying stability. The defatting process exposes the hydrophobic groups present within the YLPI, which increases total sulfhydryl content and protein surface hydrophobicity. Hot and cold defatting induced a decrease in turbidity, water-holding capacity, oil adsorption capacity, tapped and poured bulk densities. In addition, the defatting process changed the particle size of protein isolates that induced changes in their viscosity. Tryptophan spectra and protein surface hydrophobicity indicated that YLPICD and YLPIHD underwent structural conformational change during the defatting process.

Dairy, Plant, and Novel Proteins: Scientific and Technological Aspects

Alternative proteins have gained popularity as consumers look for foods that are healthy, nutritious, and sustainable. Plant proteins, precision fermentation-derived proteins, cell-cultured proteins, algal proteins, and mycoproteins are the major types of alternative proteins that have emerged in recent years. This review addresses the major alternative-protein categories and reviews their definitions, current market statuses, production methods, and regulations in different countries, safety assessments, nutrition statuses, functionalities and applications, and, finally, sensory properties and consumer perception. Knowledge relative to traditional dairy proteins is also addressed. Opportunities and challenges associated with these proteins are also discussed. Future research directions are proposed to better understand these technologies and to develop consumer-acceptable final products.

Production of Protein Concentrates from Macauba (Acrocomia aculeata and Acrocomia totai) Kernels by Sieve Fractionation

Macauba palm fruits (Acrocomia aculeata and Acrocomia totai) are emerging as sources of high-quality oils from their pulp and kernels. The protein-rich macauba kernel meal (MKM) left after oil extraction remains undervalued, mainly due to the lack of suitable deoiling parameters and integrated protein recovery methods. Therefore, the present study aimed to produce protein concentrates from MKM using sieve fractionation. The deoiling parameters, comprising pressing, milling, and solvent extraction, were improved in terms of MKM functionality. The combination of hydraulic pressing, milling to 1 mm, and the hexane extraction of A. aculeata kernels resulted in MKM with the highest protein solubility (77.1%), emulsifying activity index (181 m²/g protein), and emulsion stability (149 min). After sieve fractionation (cut size of 62 µm), this meal yielded a protein concentrate with a protein content of 65.6%, representing a 74.1% protein enrichment compared to the initial MKM. This protein concentrate showed a reduced gelling concentration from 8 to 6%, and an increased emulsion stability from 149 to 345 min, in comparison to the MKM before sieving. Therefore, sieve fractionation after improved deoiling allows for the simple, cheap, and environmentally friendly recovery of MKM proteins, highlighting the potential of macauba kernels as a new source of protein.

Flavor challenges in extruded plant-based meat alternatives: A review

Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.

Pea protein composition, functionality, modification, and food applications: A review

The demand for proteins continues to increase due to their nutritional benefits, the growing world population, and rising protein deficiency. Plant-based proteins represent a sustainable source to supplement costly animal proteins. Pea (Pisum sativum L.) is one of the most produced plant legume crops in the world and contributes to 26% of the total pulse production. The average protein content of pea is about 20%-25%. The commercial utilization of pea proteins is limited, partially due to its less desirable functionalities and beany off-flavor. Protein modification may change these properties and broaden the application of pea proteins in the food industry. Functional properties such as protein solubility, water and oil holding capacity, emulsifying/foaming capacity and stability, and gelation can be altered and improved by enzymatic, chemical, and physical modifications. These modifications work by affecting protein chemical structures, hydrophobicity/hydrophilicity balance, and interactions with other food constituents. Modifiers, reaction conditions, and degree of modifications are critical variables for protein modifications and can be controlled to achieve desirable functional attributes that may meet applications in meat analogs, baking products, dressings, beverages, dairy mimics, encapsulation, and emulsions. Understanding pea protein characteristics will allow us to design better functional ingredients for food applications.

Fermentation of Lupin Protein Hydrolysates-Effects on Their Functional Properties, Sensory Profile and the Allergenic Potential of the Major Lupin Allergen Lup an 1

Lupin protein isolate was treated using the combination of enzymatic hydrolysis (Papain, Alcalase 2.4 L and Pepsin) and lactic acid fermentation (Lactobacillus sakei ssp. carnosus, Lactobacillus amylolyticus and Lactobacillus helveticus) to investigate the effect on functional properties, sensory profile and protein integrity. The results showed increased foaming activity (2466–3481%) and solubility at pH 4.0 (19.7–36.7%) of all fermented hydrolysates compared to the untreated lupin protein isolate with 1613% of foaming activity and a solubility of 7.3 (pH 4.0). Results of the SDS-PAGE and Bead-Assay showed that the combination of enzymatic hydrolysis and fermentation of LPI was effective in reducing L. angustifolius major allergen Lup an 1 to a residual level of <0.5%. The combination of enzymatic hydrolysis and fermentation enables the production of food ingredients with good functional properties in terms of protein solubility and foam formation, with a balanced aroma and taste profile.

Effect of enzyme-assisted hydrolysis on protein pattern, technofunctional, and sensory properties of lupin protein isolates using enzyme combinations

The modification of lupin protein isolates (LPI) by means of enzymatic hydrolysis (Lupinus angustifolius cultivar Boregine) was performed with four enzyme preparations (Alcalase 2.4 L, Papain, Corolase 7089, and Neutrase 0.8 L) in a one- and two-step process to determine the efficacy for the destruction of major IgE-reactive polypeptides and the evaluation of the technofunctional and sensory properties of lupin protein hydrolysates. Combinations of Alcalase 2.4 L and Papain were most effective in the degradation of polypeptides in L. angustifolius as measured by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The enzymatic hydrolysis of the LPI increased their technofunctional properties such as protein solubility, foam activity, and emulsifying capacity almost independently of the enzyme preparation used. The sensory results showed a significant increase in bitterness from 1.9 for LPI to 5.7 for the combination of Alcalase 2.4 L and Papain in one-step process. The aroma attributes of the hydrolysates were very similar to untreated LPI. The results of this study show the possibility of enzymatic hydrolysis of LPI to destroy the major IgE-reactive polypeptides that increase the technofunctional properties of the isolates and thus their use in human nutrition as food ingredients.

Impact of alcohol washing on the flavour profiles, functionality and protein quality of air classified pea protein enriched flour

In this study the potential of aqueous solvent washing on removing off-flavours in air classified pea protein-enriched flour (PPEF) was investigated. Unpleasant flavour compounds are one of the main deterrents to the application of pulses. PPEF was treated with ethanol or isopropanol at three different concentrations (20%, 50%, and 80%) to remove the volatiles related to unpleasant beany, earthy and astringent flavours. Headspace solid phase microextraction followed by GC-MS was used to identify the flavour compounds in untreated and treated PPEF. Besides the flavour profile, changes to their proximate composition, colour, functionality and protein quality were compared among untreated and treated samples. Higher concentrations of ethanol and isopropanol (50% and 80%) showed greater effectiveness in removing flavour compounds by reducing the total peak area by 82%-94%. Protein content in all treated samples (58.2%-64.3% d.b.) increased compared to untreated PPEF (55.5%) as a result of purification due to the decrease in ash, lipid and carbohydrate content. However, alcohol treatment reduced the protein solubility and oil holding capacity in all samples by 38.3%-75.9%, and 16.7%-30.2%, respectively. Although in vitro protein digestibility was improved with the solvent treatments, the amino acid scores of those samples became lower (i.e., reduced levels of methionine, cysteine or tryptophan) resulting in up to a 27.8% reduction in in vitro protein digestibility correct amino acid scores. Both ethanol and isopropanol at 50% and 80% concentration proved to be effective in removing flavour compounds in PPEF with some modifications on the chemical compositions, protein functionalities and quality.

Techno-Functional, Nutritional and Environmental Performance of Protein Isolates from Blue Lupin and White Lupin

Similarly prepared protein isolates from blue lupin (Lupinus angustifolius) and white lupin (L. albus) were assessed in relation to their composition, functional properties, nutritional attributes and environmental impacts. Blue lupin protein isolate (BLPI) and white lupin protein isolate (WLPI) were found to be quite similar in composition, although differences in the electrophoretic protein profiles were apparent. Both lupin protein isolates (LPIs) had good protein solubility (76.9% for BLPI and 69.8% for WLPI at pH 7) and foaming properties. However, a remarkable difference in heat gelation performance was observed between BLPI and WLPI. WLPI had a minimum gelling concentration of 7% protein, whereas BLPI required 23% protein in order to form a gel. WLPI also resulted in stronger gels over a range of concentrations compared to BLPI. Nutritional properties of both LPIs were similar, with no significant differences in in vitro protein digestibility (IVPD), and both had very low trypsin inhibitor activity (TIA) and fermentable oligo-, di- and monosaccharides, and polyols (FODMAP) content. The amino acid profiles of both LPIs were also similar, with sulfur-containing amino acids (SAAs) being the limiting amino acid in each case. Environmental impacts revealed by the life cycle assessment (LCA) were almost identical for BLPI and WLPI, and in most categories the LPIs demonstrated considerably better performance per kg protein when compared to cow's whole milk powder.

Enzymatic hydrolysis of lupin protein isolates-Changes in the molecular weight distribution, technofunctional characteristics, and sensory attributes

Enzymatic hydrolysis of lupin protein isolates (LPI; Lupinus angustifolius L.) was performed with nine different protease preparations to investigate their effect on technofunctionality, sensory properties, and the integrity of the proteins to estimate the reduction of the immunoreactivity. Alcalase 2.4 L, papain, and pepsin were most effective in the degradation of the α- and β-conglutin examined by SDS-PAGE analysis, although the degree of hydrolysis only slightly increased. The technofunctional properties of LPI-solubility, emulsifying, and foaming activity-were improved by most of the proteolytic enzymes with the most impressive increase from 980% foam activity for LPI up to 3,614% foam activity for pepsin hydrolysate. The formation of bitterness, most likely linked to generation of bitter peptides, was pronounced in the Alcalase hydrolysate, while the other hydrolysates did not show an extensive increase in bitterness compared to the LPI. Other sensory attributes of the hydrolysates-with the exception of Alcalase treatment-were also very similar to the LPI. The results of this study show the potential of enzymatic degradation of LPI to modify the IgE-reacting polypeptides and to improve the technofunctionality of the isolates and therefore their use as food ingredients.

Thermal and functional characteristics of defatted bovine heart using supercritical CO2 and organic solvent

BACKGROUND

Consumer demand for low-fat foods has been increasing as a result of attempts to reduce obesity and chronic diseases. Bovine heart was defatted using supercritical CO₂ (SC-CO₂ ) at different pressures together with solvent extraction to produce a protein-based functional ingredient for low-fat food products. Thermal and functional characteristics of control and defatted samples were compared.

RESULTS

Supercritical CO₂ treatment at high pressure results in more removal of fat, producing a protein-rich defatted bovine heart (DBH). The differential scanning calorimeter (DSC) thermograms and SDS-PAGE bands for SC-CO₂ -treated DBHs were similar to those of the control sample, indicating high protein stability and better functionality. Hexane-treated DBH showed no major thermal peaks and very diffuse bands in SDS-PAGE, indicating denaturation of proteins during solvent extraction. No denaturation of proteins in SC-CO₂ -treated DBHs resulted in significantly higher water/oil absorption capacities (3320.00 and 2630.00 g kg^-1 , respectively), total soluble solids (822.20 and 208.71 g kg^-1 at pH 3.5 and 6.5, respectively), foaming capacities (149.37%), and emulsion activity (66.89%) than the hexane-treated DBH.

CONCLUSION

Supercritical CO₂ treatment of DBH led to higher thermal stability and functional properties than the control and hexane-treated DBH. Defatted bovine heart using SC-CO₂ can be a functional ingredient for various low-fat and high-protein food products for health-conscious consumers. © 2018 Society of Chemical Industry.

Reduction of off-flavours and the impact on the functionalities of lentil protein isolate by acetone, ethanol, and isopropanol treatments

The changes of flavour profiles in lentil protein isolate (LPI) in response to organic solvent treatments (acetone, ethanol, and isopropanol; 35-95% v/v), and the resulting impacts on the isolate colour and physicochemical and functional attributes were investigated. The major constituents of volatile compounds were aldehydes (∼46.59%) and (E,E)-3,5-octadien-2-one (∼31.79%) in the untreated LPI. Acetone treatment greatly raised ketones by ∼79.59%. In contrast, ethanol and isopropanol, except at 95% (v/v), significantly lowered total volatile compounds and had higher protein contents (∼84.55%) than the others (∼76.98%); surface charge, surface hydrophobicity, solubility and emulsion stability of these LPIs were examined. LPIs obtained from 75% (v/v) ethanol and isopropanol treatments showed slightly lower solubility but improved surface hydrophobicity to produce emulsions with a similar stability as compared with the untreated LPI. Overall, ethanol and isopropanol treatments (75% v/v) produced high quality off-flavour-reduced LPIs which may be used in various food systems.

Enzyme-Linked Immunosorbent Assay (ELISA)

Food allergy is a public health concern especially after recognizing its constantly increased prevalence and severity. Despite careful reading of food ingredient statements, food allergic individuals may experience reactions caused by "hidden", "masked", or "contaminated" proteins that are known major allergens. Many techniques have been developed to detect even small traces of food allergens, for clinical or laboratory purposes. Enzyme-linked immunosorbent assay (ELISA) is one of the best validated and most routinely used immunoassay in allergy research, in allergy diagnosis in allergy-related quality control in various industries. Although as a technique it has been implemented for the last 45 years, the evolution in biochemistry allowed the development of ultrasensitive ELISA variations that are capable of measuring quantities in the scale of picograms, rendering ELISA attractive, robust, and very famous.

Physicochemical and functional properties of beany flavour-free bambara groundnut protein isolate

BACKGROUND

Off-odour/flavour (beany) associated with bambara groundnut protein isolate (BGPI), due to oxidative degradation of lipids during either storage or processing, is a major problem limiting its application in foods. In this study, effects of heat treatment (50-80 °C) in combination with ethylenediaminetetraacetic acid (EDTA) on functional and sensory properties of BGPI were investigated.

RESULTS

BGPI prepared in the presence of EDTA had lower lipoxygenase and trypsin-inhibitory activities than BGPI prepared in the absence of EDTA, regardless of the heating temperature used (P < 0.05). Inactivation of lipoxygenase was associated with lowered peroxide value, thiobarbituric acid-reactive substances and beany odour/flavour intensity in BGPI stored at room temperature for 30 days. BGPI with heat treatment at temperatures lower than 70 °C had similar protein patterns to BGPI prepared by the typical process, except for the occurrence of proteins with molecular weight 70-82 kDa. BGPI with heat treatment showed decreased protein solubility but increased surface hydrophobicity and sulfhydryl group content. BGPI prepared in the presence of EDTA exhibited higher emulsion activity and stability indices as well as higher foam expansion and stability than BGPI prepared in the absence of EDTA, regardless of heating temperature (P < 0.05).

CONCLUSION

Heat treatment at 70 °C in the presence of 100 mmol L(-1) EDTA effectively reduced beany flavour development and enhanced the functionality of BGPI.