Protein Extracts Research Articles

Study on the induced polymeric protein aggregation and immunoreactivity in biscuits enriched with peanut flour

This work deals with the study on the protein extractability of biscuits incurring different percentages of roasted peanut flour. The presence of two different flours influenced the rate of protein aggregation and protein extractability, according to the percentage of roasted peanut flour added to the formulation and assessing these features by testing the use of two buffers. Results showed that gluten network arrangement of biscuits was influenced by the flours mixture besides the baking, with possible different protein organizations. Protein extractability was affected, underlining a higher content of protein aggregates at high molecular weight especially with the addition of 20% of peanut flour, characterized by hydrophobic and reducible covalent bonds, as suggested by the higher extractability obtained with the buffer with chaotropic and reducing agents.These results suggested a possible induced supramolecular protein organization in these products, which could affect the immunoreactivity of the main allergens occurred in the formulation.

Enhancing protein extraction from heterotrophic Auxenochlorella protothecoides microalgae through emerging cell disruption technologies combined with incubation

This study evaluated pulsed electric fields (PEF) and ultrasonication (US) combined with incubation to enhance cell disruption and protein extraction from Auxenochlorella protothecoides, comparing them to conventional high-pressure homogenization (HPH). A 5 h incubation enhanced protein yield by 79.4 % for PEF- and 27.2 % for US-treated samples. Extending the incubation to 24 h resulted in a total yield increase of 122 % for PEF (0.25 ± 0.03 kgEP kgTP−1) and 51.9 % for US. Autofermentation in untreated cells after 24 h resulted in protein release with lower yields than all other treated and incubated samples. While HPH had the highest protein yield (0.58 ± 0.04 kgEP kgTP−1), PEF-incubation after 5 h (56.6 ± 5.3 MJ kgEP−1) and 24 h (49.5 ± 3.7 MJ kgEP−1) were 1.5 and 1.7-times more energy-efficient than HPH (82.9 ± 7.8 MJ kgEP−1). PEF combined incubation is an energy-efficient and targeted protein extraction method in heterotrophic A. protothecoides biorefinery.

Physicochemical characteristics and microbial diversity of sous vide scallops (Chlamys farreri) during chilled storage

This study investigated the impact of sous vide (SV) cooking methods on the physical and chemical characteristics as well as the microbial composition of scallops (Chlamys farreri) over a 30 days period of refrigerated storage. Scallop treatments were divided into two groups: CS (scallops vacuum-packed and then steamed for 30 min at 75 °C) and CK (scallops steamed for 15 min at 100 °C). With the increase in refrigeration time, the total volatile basic nitrogen (TVBN), pH, cooking loss, microbial content, and malondialdehyde (MDA) content gradually increased, while the water-soluble protein extraction rate and the myofibrillar protein (MP) extraction rate of the CS and CK samples significantly decreased. Notably, the SV steaming treatment effectively reduced microbial degradation of proteins, improved water retention of scallop samples, and maintained high MP extraction as compared to CK samples (MP content ranged from 1.09% to 2.50% in the CK group and 1.75%–3.33% in the CS group). During the late stages of refrigeration, conventionally cooked scallops (CK) were dominated by Pseudomonas and Psychrobacter, with the ability to produce biogenic amines, while SV steamed scallops were dominated by Psychrobacillus. Furthermore, a link was discovered between the microbial community and the physicochemical parameters.

Fish Oil Supplementation Mitigates High-Fat Diet-Induced Obesity: Exploring Epigenetic Modulation and Genes Associated with Adipose Tissue Dysfunction in Mice.

This study investigated the effects of fish oil (FO) treatment, particularly enriched with eicosapentaenoic acid (EPA), on obesity induced by a high-fat diet (HFD) in mice. The investigation focused on elucidating the impact of FO on epigenetic modifications in white adipose tissue (WAT) and the involvement of adipose-derived stem cells (ASCs). C57BL/6j mice were divided into two groups: control diet and HFD for 16 weeks. In the last 8 weeks, the HFD group was subdivided into HFD and HFD + FO (treated with FO). WAT was removed for RNA and protein extraction, while ASCs were isolated, cultured, and treated with leptin. All samples were analyzed using functional genomics tools, including PCR-array, RT-PCR, and Western Blot assays. Mice receiving an HFD displayed increased body mass, fat accumulation, and altered gene expression associated with WAT inflammation and dysfunction. FO supplementation attenuated these effects, a potential protective role against HFD-induced obesity. Analysis of H3K27 revealed HFD-induced changes in histone, which were partially reversed by FO treatment. This study further explored leptin signaling in ASCs, suggesting a potential mechanism for ASC dysfunction in the obesity-rich leptin environment of WAT. Overall, FO supplementation demonstrated efficacy in mitigating HFD-induced obesity, influencing epigenetic and molecular pathways, and shedding light on the role of ASCs and leptin signaling in WAT dysfunction associated with obesity.

Can gene-editing accelerate the protein shift? Consumer acceptance of an upcycled meat-substitute

Transforming waste in the production stage to food (upcycling) can contribute to increased environmental sustainability in the food systems. The side-stream in potato starch production contains protein, and gene-editing enables upcycling of potato-protein while avoiding the use of chemical processes in the extraction of food grade protein. We explore the demand for products containing this upcycled protein. Data were collected via an online survey of 1508 Swedish consumers who completed a choice experiment in which they selected among different sausages made from meat, soy, peas or potato-protein. Although meat is the most preferred product type, respondents choose potato-protein over soy and pea-protein. Upcycled potato-protein products are predicted to draw on the market share for meat more than from soy and pea-protein, suggesting considerable potential environmental benefits. The acceptance of upcycled products is not significantly different depending on if the upcycling is achieved by a chemical process or gene-editing (CRISPR-Cas9) techniques. We discuss the importance of the legal status of gene-editing and the role this may play in reducing food waste. Further, we discuss how policy makers can play an important role in reducing food waste, by means of regulations and by encouraging public and private initiatives that accommodate upcycling in the different stages of food production.

Gut microbiota remodeling drived by dietary millet protein prevents the metabolic syndrome

Metabolic syndrome (MetS) is a chronic disease associated with the disturbance of gut microbiota homeostasis. Metabolites derived from gut microbes play essential roles in MetS prevention and therapy. Here, we focused on the inhibitory effect of the extract of millet bran protein (EMBP) on a high-fat diet (HFD)-induced MetS, aiming to identify gut microbiota and their metabolites that involve in the anti-MetS activity of EMBP. The obesity, chronic inflammation, insulin resistance in MetS mouse models were abolished after EMBP treatment. The protective mechanism of EMBP against HFD-induced MetS may depend on improved gut barrier function. Using microbiome analysis, we found that EMBP supplementation improved gut microbiome dysbiosis in MetS mice, specifically upregulating Bacteroides acidifaciens. The fecal microbiota transplantation (FMT) also demonstrated this phenomenon. In addition, metabolomic analysis showed that EMBP mediates metabolic profiling reprogramming in MetS mice. Notably, a microbiota-derived metabolite, gamma-aminobutyric acid (GABA), is enriched by EMBP. In addition, exogenous GABA treatment produced a similar protective effect to EMBP by improving NRF2-dependent gut barrier function to protect HFD-induced MetS. The results suggest that EMBP suppress host MetS by remodeling of gut microbiota as an effective candidate for next-generation medicine food dual purpose dietary supplement to intervene in MetS.

Study on electrostatic separation technology and characterization of shrimp shell protein

Shrimp shell protein is a high-quality protein with wide-ranging applications in feed, pharmaceuticals, and food industries. However, current methods for its production often involve the use of harsh chemicals, resulting in the generation of polluting effluents, making green alternatives highly desirable. This study combined demineralization of shrimp shell (Fenneropenaeus chinensis, Osbeck, 1765) with ultrafine grinding and electrostatic separation techniques to extract and separate the protein. The research findings revealed that shrimp shell contain 40.64 ± 0.52 % protein, which increased to 52.61 ± 1.12 % after demineralization treatment. Impact grinding, compared with cutting grinding, facilitated the production of demineralized shrimp shell ultrafine powder with more uniform distribution and smaller particle size. However, only demineralized shrimp shell powder obtained through cutting grinding achieved an increase in protein purity from 61.82 ± 0.75 % to 72.72 ± 0.83 % after electrostatic separation. The electrical properties of shrimp shell protein and chitin suggest that shrimp shell protein is more conductive than chitin, while shrimp shell chitin is more insulating and less prone to charge exchange with the counter material in a direct current electric field. The total amino acid content of shrimp shell protein obtained through electrostatic separation (715.831 mg/g protein) was higher than that obtained through traditional wet extraction (533.455 mg/g protein). Additionally, the amino acid score (AAS) of shrimp shell protein obtained via electrostatic separation was higher compared to that obtained via wet extraction. The wet extraction process significantly influenced the nutritional and structural properties of shrimp shell protein. This study confirms the potential application of electrostatic separation technology in the extraction of animal-derived shrimp shell protein.

Enhanced recovery of R-phycoerythrin using recombination cell-assisted pressurized fluid extraction: yield, characterization, and antioxidant evaluation

The recovery of phycobiliproteins, with an emphasis on R-phycoerythrin (R-PE), from Solieria filiformis macroalgae was investigated in the current study. This is accomplished using an environmentally friendly method known as pressurized fluid extraction. Phycobiliprotein production was analyzed over time, considering four different parameters: i) solvents (ultrapure water and phosphate buffer), ii) macroalgae particle sizes, iii) stirring, and iv) pressure of 200 to 800 bar. Notably, the highest R-PE yield reached an impressive 22.53 mg/g dry biomass. The best extraction conditions were identified as a macerated structure, employing a combination of 500 bar pressure and agitation facilitated by a recombination cell. R-phycocyanin (R-PC) was also extracted with a 3.70 mg/g yield. Two distinct extracts, crude and precipitate, underwent comprehensive characterization. Extracted R-PE exhibited an α-helix structure (80.51–90.39 %), suggesting the existence of other proteins in both extracts. Three different subunits, α (15 kDa), β (21 kDa), and γ (29 kDa), were segregated under SDS-PAGE. Moreover, both extracts demonstrated antioxidant capacity, achieving a 99.55 % reduction in 2,2-diphenyl-1-picryl-hydrazil (DPPH) radicals and a 13.94 % chelation of ferrous ions. This study reports the extraction of biomolecules using the recombination cell for the first time in the literature, proving an appealing alternative for non-aggressive extraction with inherent biological activity. These findings underscore the potential applications of these extracted phycobiliproteins in various fields, including biotechnology and health.

Pulsed Electric Fields assisted extraction of proteins and phycocyanin from Arthrospira platensis biomass: A kinetic study

The objective of this work was the investigation of the kinetics of protein and C-phycocyanin extraction from Arthrospira platensis (Spirulina) biomass assisted by Pulsed Electric Fields (PEF). Fresh, untreated and PEF-treated (7.8kV/cm, 0-137.6kJ/kg) biomass was suspended in water and incubated at 30-50 °C for up to 24h. Protein and C-phycocyanin recovery kinetics exhibited a sigmoidal behavior. The increase in treatment specific energy and incubation temperature up to 40 °C led to significant extraction acceleration. A treatment of 137.6kJ/kg prior to incubation at 40 °C led to the minimization of protein characteristic incubation time (2.3h vs. 14.4h and 10.4h of untreated sample at 30 and 40 °C, respectively). At 50 °C a significant reduction of the extraction yield was observed due to the inactivation of the proteolytic enzymes. Higher treatment specific energy led to increased C-phycocyanin purity of the extracts at 40 °C. The maximization of the C-phycocyanin extract purity factor (1.14 vs 0.66 for untreated samples) was achieved with a treatment at 137.6kJ/kg and incubation at 40 °C for 3h.

Integrated multi-omics reveals the relationship between growth performance, rumen microbes and metabolic status of Hu sheep with different residual feed intakes

Residual feed intake (RFI) is a metric that provides a more accurate measure of feed efficiency. The lower the RFI, the higher the feed efficiency. The changes in the host microbiome and metabolome contribute to the greater feed efficiency of low RFI (LRFI) animals. The aim of this study was to explore the differences in rumen microorganisms, rumen metabolites and plasma metabolites of Hu sheep with differing RFI through the microbiome and metabolome. A total of 80 Hu sheep were used. The experiment consisted of a 15-d pretrial period and a 128-d experimental period. The RFI in the experimental period was calculated for all sheep, and the sheep were screened into high RFI (HRFI, n = 8) and LRFI (n = 8) groups. The HRFI and LRFI sheep did not differ in their initial and final body weights, average daily gain and body measurements, but the dry matter intake of LRFI sheep was significantly decreased (28.4%, P < 0.001). The sheep with LRFI had higher digestibility of crude protein (P = 0.010) and ether extract (P = 0.010) compared to HRFI group. The concentrations of acetate (P = 0.036), propionate (P = 0.010), valerate (P = 0.027) and total volatile fatty acids (P = 0.048) in rumen of LRFI group were higher compared to HRFI group. The results of 16S rDNA sequencing indicated that the sheep with LRFI had higher proportions of Prevotella genus in rumen liquid (P = 0.031). The rumen metabolome and plasma metabolome results showed that the citrate cycle, pyruvate metabolism and alanine, aspartate and glutamate metabolism processes were more active for sheep in LRFI group, which provided more energy substrate such as malic acid, oxoglutaric acid and citric acid. In conclusion, sheep with LRFI can utilize feed more efficiently, and the more active energy metabolism pathway and the production of energy substances may account for the higher feed efficiency.

Assessing the environmental footprint of alternative green biorefinery protein extraction techniques from grasses and legumes

The significant grasslands of Europe and its member states represents a significant feedstock opportunity for circular bioeconomy development. The development of green biorefineries (GBR), to supply protein for the feed industry from grass, could help many European member states to address significant deficits in protein availability and reduce imports. The current study assesses the environmental footprint of alternative GBR protein extraction techniques from grasses and legumes using life cycle assessment. The focus is on comparing feedstock and technology pathways that could displace soya bean imports. The study finds that leaf protein concentrate (LPC) produced from grass had an improved environmental performance when compared to soya bean meal (SBM), across the assessed feedstock (perennial ryegrass or grass-clover mixtures) and technology pathways (one-stage maceration versus multi-stage maceration). For example, in the case of Climate Change the emission intensity for LPC was 57–85 % lower per tonne of crude protein (CP) compared with SBM. Acidification burdens were 54–88 % lower, and Eutrophication: Freshwater burdens 74–89 % lower. Some scenarios of GBR produced LPC with a larger Energy Resources: Non-Renewable burden than SBM, though this could be mitigated with higher renewable energy (biogas and wind energy) integration within the scenario. Grass-clover scenarios generally achieved a lower intensity of emissions compared to ryegrass scenarios, particularly in the category of Climate Change, where feedstock cultivation represents a significant contributor to impacts. Overall, GBR can produce quality protein with a lower environmental burden than SBM, but choice of feedstock and system design are critical factors for overall environmental performance.

Minimizing anti-nutritional factors in wet protein extraction from Swedish faba beans through the application of response surface methodology

Faba beans, rich in protein and ideal for Swedish cultivation, are limited in food industry use due to anti-nutritional factors (ANFs) that hinder nutrient absorption. An extraction method was developed in our study to mitigate ANFs in faba beans, using aqueous alkaline methods and isoelectric precipitation with differential salt concentration. This method yielded 15.8 g of protein per 100 g of flour, with a protein concentration exceeding 83% of the total extract. It reduced ANFs like phytic acid (28.0%), lectins (87.5%), vicine (98.5%), and convicine (99.7%). Extraction conditions were optimized using response surface methodology, identifying pH 6, 2 h, and 20 °C as the most effective parameters, achieving an 86% reduction in phytic acid, closely matched the model's predictions (R2 = 0.945). This method effectively reduced ANFs, offering a sustainable approach for producing proteins suitable for diverse food products, including plant-based alternatives.

Elucidating regulation of polyhydroxyalkanoate metabolism in Ralstonia eutropha: Identification of transcriptional regulators from phasin and depolymerase genes

Despite the ever-growing research interest in polyhydroxyalkanoates (PHAs) as green plastic alternatives, our understanding of the regulatory mechanisms governing PHA synthesis, storage, and degradation in the model organism Ralstonia eutropha remains limited. Given its importance for central carbon metabolism, PHA homeostasis is probably controlled by a complex network of transcriptional regulators. Understanding this fine-tuning is key for developing improved PHA production strains thereby boosting the application of PHAs. We conducted promoter pull-down assays with crude protein extracts from R. eutropha Re2058/pCB113, followed by LC-MS/MS, to identify putative transcriptional regulators involved in the expression control of PHA metabolism, specifically targeting phasin phaP1 and depolymerase phaZ3 and phaZ5 genes. The impact on promoter activity was studied in vivo using β-galactosidase assays and the most promising candidates were heterologously produced in Escherichia coli and their interaction with the promoters investigated in vitro by Electrophoretic Mobility Shift Assays. We could show that R. eutropha DNA-binding XRE-family-like protein H16_B1672, specifically binds the phaP1 promoter in vitro with a KD of 175 nM and represses gene expression from this promoter in vivo. Protein H16_B1672 also showed interaction with both depolymerase promoters in vivo and in vitro suggesting a broader role in the regulation of PHA metabolism. Furthermore, in vivo assays revealed that the H-NS-like DNA-binding protein H16_B0227 and the peptidyl-prolyl cis-trans isomerase PpiB, strongly repress gene expression from PphaP1 and PphaZ3, respectively. In summary, this study provides new insights into the regulation of PHA metabolism in R. eutropha, uncovering specific interactions of novel transcriptional regulators.

An optimized protocol for pig intestinal mucosa proteomics

The overall well-being of organisms is widely recognized to be closely intertwined with their intestinal health. The intestinal mucosal layer plays a pivotal role in ensuring the proper functioning of the intestine, a fact observed not only in humans but also in animals like pigs. Any alterations to the mucosal layer of a pig's intestine can potentially disrupt its functionality, thereby impacting the animal's health and productivity. Mass spectrometry-based proteome analysis serves as a valuable tool in investigating the intricate dynamics of the proteome within the intestinal mucosa. Such studies hold promise in uncovering causal relationships between mucosal changes and overall health outcomes in pigs. It is anticipated that insights gathered from proteome studies will inform future strategies aimed at enhancing the health and productivity of pigs. However, the research field lacks a standardized and detailed method to extract proteins from pig intestinal mucosa and prepare proteins for proteome analysis. In the present study, we evaluated three alternative S-Trap-based protocols for analyzing ileal mucosal scrapings from pigs. Samples were either freeze-dried and treated as solid samples or ground in liquid nitrogen, categorized as either solid or liquid samples. In our analysis, a total of 2840 proteins were identified across all samples. Through statistical analysis and gene ontology examinations, we investigated potential differences between the three approaches. Even though our findings revealed no significant differences among the three methods, we propose the use of the protocol wherein samples are freeze-dried and treated as solid for protein extraction. This protocol stands out as the most convenient and practical option, offering ease of use and ensuring consistent and reliable results. By establishing a standardized approach, we aim to advance research efforts in understanding pig intestinal health. SignificanceThe development of an optimized protocol for protein extraction of intestinal mucosal scrapings in pigs addresses a gap in the field and enhances future research on pig intestinal health. By use of the protocol and mass spectrometry-based proteome analysis, valuable insights for improving the health and productivity of pigs can be presented. Studying the complex dynamics of the proteome within the intestinal mucosa, potentially identifying links between mucosal changes and health outcomes, provides us with information about the critical connection between intestinal health and the overall well-being and productivity of pigs. By creating a standardized approach, consistent, reliable, and reproducible results can be obtained for this type of research.

Effects of genetic diversity on the allergenicity of peanut (Arachis hypogaea) proteins: identification of the hypoallergenic accessions using BALB/c mice model and in silico analysis of Ara h 3 allergen cross-reactivity

This study investigated the effects of genetic diversity in the allergenicity of peanut and assessed the allergenic capacity of six Arachis hypogaea accessions using a Balb/c mouse model. It also explored potential cross-reactivities between Ara h 3 (peanut allergen) and Gly m (soybean allergen) using computational tools. Female Balb/c mice were injected with peanut protein extracts and alum. Serum-specific antibodies (IgE, IgGt, IgG1, IgG2a) were measured using ELISA, and allergic protein profiles were examined via western blot. Structural homology, B cell epitopes, and molecular interactions between Ara h 3 and Gly m with human IgE were also investigated. The mice developed high sIgE and sIgG1 responses, with antibodies recognizing 19 bands on western blot. Notably, Saharan accessions showed unique features such as no bands on western blot profiles, reduced anaphylactic symptoms, lower IgE titers, and less intestinal tissue damage. Molecular docking results suggest significant cross-allergenicity, supported by allergenicity predictions and structural homology analysis. This comprehensive analysis provides insights into shared epitopes, potential competition for binding sites, and molecular dynamics of cross-reactive responses, enhancing understanding of food allergen interactions. The study recommends using Algerian Sahara peanut accessions in breeding, genomics studies, and industry for safer peanut options for individuals with allergies. SignificanceThe significance of this study lies in its contribution to addressing a major public health issue: peanut allergy, which represents a significant cause of anaphylaxis affecting numerous individuals and families worldwide. By exploring the genetic diversity of peanut proteins and identifying hypoallergenic accessions through experimental and computational approaches, this research offers valuable insights for mitigating allergic reactions. The findings highlight that certain accessions from the Saharan region exhibit reduced allergenicity, resulting in attenuated anaphylactic symptoms, lower IgE levels, and reduced intestinal damage in murine models. Furthermore, the study's in silico analysis sheds light on the issue of cross-reactivity between peanut and soybean allergens, providing crucial information for understanding allergen interactions at the molecular level. Overall, this research contributes to advancing knowledge in the field of food allergen research and has practical implications for improving the quality of life for individuals allergic to peanuts, particularly through the selection of safer peanut varieties and their cultivation.

A prospective study of the proteome of equine pre-implantation embryo.

The present study was conducted to investigate the global proteome of 8-day-old equine blastocysts. Follicular dynamics of eight adult mares were monitored by ultrasonography and inseminated 24 h after the detection of a preovulatory follicle. Four expanded blastocysts were recovered, pooled, and subjected to protein extraction and mass spectrometry. Protein identification was conducted based on four database searches (PEAKS, Proteome Discoverer software, SearchGUI software, and PepExplorer). Enrichment analysis was performed using g:Profiler, Panther, and String platforms. After the elimination of identification redundancies among search tools (at three levels, based on identifiers, peptides, and cross-database mapping), 1977 proteins were reliably identified in the samples of equine embryos. Proteomic analysis unveiled robust metabolic activity in the 8-day equine embryo, highlighted by an abundance of proteins engaged in key metabolic pathways like the TCA cycle, ATP biosynthesis, and glycolysis. The prevalence of chaperones among highly abundant proteins suggests that regulation of protein folding, and degradation is a key process during embryo development. These findings pave the way for developing new strategies to improve equine embryo media and optimize invitro fertilization techniques.

Exploring the anti-inflammatory effects of postbiotic proteins from Lactobacillus delbrueckii CIDCA 133 on inflammatory bowel disease model

Lactobacillus delbrueckii CIDCA 133 is a promising health-promoting bacterium shown to alleviate intestinal inflammation. However, the specific bacterial components responsible for these effects remain largely unknown. Here, we demonstrated that consuming extractable proteins from the CIDCA 133 strain effectively relieved acute ulcerative colitis in mice. This postbiotic protein fraction reduced the disease activity index and prevented colon shortening in mice. Furthermore, histological analysis revealed colitis prevention with reduced inflammatory cell infiltration into the colon mucosa. Postbiotic consumption also induced an immunomodulatory profile in colitic mice, as evidenced by both mRNA transcript levels (Tlr2, Nfkb1, Nlpr3, Tnf, and Il6) and cytokines concentration (IL1β, TGFβ, and IL10). Additionally, it enhanced the levels of secretory IgA, upregulated the transcript levels of tight junction proteins (Hp and F11r), and improved paracellular intestinal permeability. More interestingly, the consumption of postbiotic proteins modulated the gut microbiota (Bacteroides, Arkkemansia, Dorea, and Oscillospira). Pearson correlation analysis indicated that IL10 and IL1β levels were positively associated with Bacteroides and Arkkemansia_Lactobacillus abundance. Our study reveals that CIDCA 133-derived proteins possess anti-inflammatory properties in colonic inflammation.

Extraction of proteins from six seaweeds of south-east coast of India: Proximate composition and effect of process variables on protein solubilisation

Extraction of proteins from six seaweeds of south-east coast of India: Proximate composition and effect of process variables on protein solubilisation

Experimental evaluation of the process of protein removal from waste shrimp shells using papaya and pineapple juice solution

This research aims to improve the quality of chitin obtained from process protein extraction for shrimp shells. Previous studies showed that for the synthesis of chitosan, deproteinization, and demineralization is carried out by alkali and acid treatment, combined with heating, which affects the biosecurity of the material. Therefore, this study aims to remove protein from waste shrimp shells to purify chitin using a simple and safe green chemical approach (using pineapple and papaya juice solutions) and safe method. The raw shrimp shells were treated in steps: deproteinization with pineapple and papaya solutions for 12, 24, 36, and 48 h, varying immersion volumes from 10 mL to 60 mL. The experimental results showed that the protein in the shrimp shell was removed at 7.37% for freshwater shrimp (7.14%), higher than that of saltwater shrimp. The pineapple juice solution removed the protein better than the papaya juice.

Application of Turbiscan Lab® to study the mechanism of fining in red wine using a specific yeast protein extract: A comparison with gelatine

Fining of wines using proteins is a standard practice in the winemaking process. Gelatine is a common fining agent used for red wines. However, the consumer demand for wines that are free of animal-derived products has reinforced the search for alternative protein sources such as yeast origin as the latter is originally present in wine. In 2012, the International Organization of Vine and Wine (OIV) authorized yeast protein extract (YPE) as a processing aid for the fining of musts and wines (OIV-Eno 452–2012). The present work aimed at better understanding the fining mechanisms of a specific YPE, to evaluate the part played by interactions in solution with polyphenols, but also at the interfaces with suspended particles. Polyphenols from the soluble phase of red wine were separated from the suspended particles by centrifugation, and these particles were resuspended in a wine model solution. Interactions with YPE were studied with each fraction separately through static multiple light scattering (SMLS) using the Turbiscan Lab® apparatus and optical microscopy. The impact on wine color and astringency was assessed by UV–visible spectrophotometry and BSA assay test. Faster aggregation and sedimentation kinetics were observed with gelatine than with YPE, but the levels of clarification and lees were similar for both fining agents after a couple of hours (4 h maximum). Gelatine resulted in higher tannin and pigment removal, likely to decrease astringency but also derived pigments involved in red wine color stability. Meanwhile, the impact of the YPE was moderate, likely to modulate astringency while preserving wine color and structure. In addition to interacting directly with polyphenols in solutions such as gelatine, YPE exhibited the additional ability to trap particles and promote their sedimentation in the absence of tannins. This double performance of the YPE used in this work, is likely to guarantee an effective fining of red wines as well as for low tannin content matrices such as rosé and white wines.