Production, digestibility and allergenicity of hemp (Cannabis sativa L.) protein isolates

Advanced Characterization of Hemp Flour (Cannabis sativa L.) from Dacia Secuieni and Zenit Varieties, Compared to Wheat Flour

The advanced characterization of flour from hemp seeds (edible fruits of Cannabis sativa L.) from the Dacia Secuieni and Zenit varieties, compared to wheat flour, was studied in this research. The aim was to present the characterization of 2 varieties, out of the 70 accepted in Europe, for human consumption. The varieties selected from hemp meet the THC level requirement (0.3 or 0.2% of the dry weight of the reproductive part of the female flowering plant) in seeds. Hemp flour was obtained by grinding. The flour samples were evaluated for physicochemical parameters (moisture, crude protein, lipids, ash, crude fiber), the content of micro and macro elements, fatty acids, amino acids, and carbohydrates. The total proteins in hemp flour are found in larger quantities by over 35% compared to wheat flour, and the lipids reach the threshold of 28%. The amount of mineral substances exceeds 3% in hemp flour, and the fibers exceed 26%, compared to 0.61% for wheat flour. The predominant mineral substances were K, Ca, Mg, p, Fe, and Mn. The predominant fatty acids were the unsaturated ones, predominantly being linoleic acid, followed by oleic and gamma-linoleic acid. In the case of amino acids, the highest amount is found in glutamic acid for hemp flours. As for carbohydrates, sucrose is found in the largest amount, followed by glucose and fructose. In conclusion, hemp flours have superior non-traditional characteristics to wheat flour, being a potential raw material for fortifying food or using them as such, having beneficial effects of consumption on the proper functioning of the human body.

Identification and Characterization of the Seed Storage Proteins and Related Genes of Cannabis sativa L

Hemp (Cannabis sativa L.) seed is emerging as a novel source of plant protein owing to its rich protein content and reasonable nutritional structure. In the current study, the storage proteins of hemp seed were extracted using different methods. The modified Osborne method yielded maximum extraction of the hemp seed storage proteins, while degreasing had little effect on the hemp seed protein (HSP) extraction. Protein identification results revealed that 11S globulin (edestin) was the most abundant protein in hemp seed, and the molecular weights of the two subunits of this protein were ~35 and 20 kDa, respectively. The second most abundant protein was 2S albumin (Cs2S), with a molecular weight of ~14–15 kDa. The least abundant protein was 7S vicilin-like protein (Cs7S), with a molecular weight of ~47 kDa. Subsequently, gene families encoding these three storage protein classes, including three genes for edestin, two for Cs2S, and one for Cs7S, were cloned and then analyzed for amino acid composition and structure. The three edestins were different in their amino acid sequences and calculated molecular weights. The analysis of coding sequences revealed a higher percentage of similarity (62.7%) between Edestin1 and Edestin3, while the similarity decreased significantly to ~57% between Edestin1 and Edestin2, and 58% between Edestin2 and Edestin3. The calculated protein molecular weight was the highest for the protein encoded by Edestin1 and the smallest for the protein encoded by Edestin2. All three edestins were rich in arginine, while Edestin3 had a higher methionine content relative to that in the other two, which proved that Edestin3 had a better nutritional value. Cs2S and Cs7S were different from those reported in previous studies. Therefore, it could be inferred that amino acid composition varies with different hemp cultivars. The current research brought significant theoretical advance in illuminating the understanding of hemp seed storage protein and would have significance for future research on improving the nutritional quality of hemp seed and developing bioactive peptides.

Dietary Fiber: Fractionation, Characterization and Potential Sources from Defatted Oilseeds

Dietary fiber (DF) has wide applications, especially in the food and pharmaceutical industries due to its health-promoting effects and potential techno-functional properties in developing functional food products. There is a growing interest in studies related to DF; nevertheless, there is less focus on the fractionation and characterization of DF. The characteristics of DF fractions explain their functionality in food products and provide clues to their physiological effects in food and pharmaceutical industrial applications. The review focuses on a brief introduction to DF and methods for its fractionation. It discusses the characterization of DF in terms of structural, physicochemical and rheological properties. The potential sources of DF from selected defatted oilseeds for future studies are highlighted.

Multispecies Identification of Oilseed- and Meat-Specific Proteins and Heat-Stable Peptide Markers in Food Products

Consumer demand for both plant products and meat products enriched with plant raw materials is constantly increasing. Therefore, new versatile and reliable methods are needed to find and combat fraudulent practices in processed foods. The objective of this study was to identify oilseed species-specific peptide markers and meat-specific markers that were resistant to processing, for multispecies authentication of different meat and vegan food products using the proteomic LC-MS/MS method. To assess the limit of detection (LOD) for hemp proteins, cooked meatballs consisting of three meat species and hemp cake at a final concentration of up to 7.4% were examined. Hemp addition at a low concentration of below 1% was detected. The LOD for edestin subunits and albumin was 0.9% (w/w), whereas for 7S vicilin-like protein it was 4.2% (w/w). Specific heat-stable peptides unique to hemp seeds, flaxseed, nigella, pumpkin, sesame, and sunflower seeds, as well as guinea fowl, rabbit, pork, and chicken meat, were detected in different meat and vegan foods. Most of the oilseed-specific peptides were identified as processing-resistant markers belonging to 11S globulin subunits, namely conlinin, edestin, helianthinin, pumpkin vicilin-like or late embryogenesis proteins, and sesame legumin-like as well as 2S albumins and oleosin isoforms or selected enzymic proteins.

Biochemical aspects of seeds from Cannabis sativa L. plants grown in a mountain environment

Cannabis sativa L. (hemp) is a versatile plant which can adapt to various environmental conditions. Hempseeds provide high quality lipids, mainly represented by polyunsaturated acids, and highly digestible proteins rich of essential aminoacids. Hempseed composition can vary according to plant genotype, but other factors such as agronomic and climatic conditions can affect the presence of nutraceutic compounds. In this research, seeds from two cultivars of C. sativa (Futura 75 and Finola) grown in a mountain environment of the Italian Alps were analyzed. The main purpose of this study was to investigate changes in the protein profile of seeds obtained from such environments, using two methods (sequential and total proteins) for protein extraction and two analytical approaches SDS-PAGE and 2D-gel electrophoresis, followed by protein identification by mass spectrometry. The fatty acids profile and carotenoids content were also analysed. Mountain environments mainly affected fatty acid and protein profiles of Finola seeds. These changes were not predictable by the sole comparison of certified seeds from Futura 75 and Finola cultivars. The fatty acid profile confirmed a high PUFA content in both cultivars from mountain area, while protein analysis revealed a decrease in the protein content of Finola seeds from the experimental fields.

Proteomic analysis of oilseed cake: a comparative study of species-specific proteins and peptides extracted from ten seed species

BACKGROUND

In recent years there has been a visible trend among consumers to move away from consuming meat in favor of plant products. Meat producers have therefore been trying to meet the expectations of consumers by introducing new products to the food market with a greater proportion of plant ingredients. Meat products are enriched not only by the addition of vegetable oils but also by ground or whole oilseeds or their preparation. In this study, we present in-solution tryptic digestion and an ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS)-based proteomics approach to investigate specific proteins and peptides of ten oilseed cakes, by-products of cold pressing oil from coconut, evening primrose, hemp, flax, milk thistle, nigella, pumpkin, rapeseed, sesame, and sunflower seeds, for authentication purposes.

RESULTS

We identified a total of 229 unique oilseed proteins. The number of specific proteins varied depending on the sample, from 4 to 48 in evening primrose and sesame. Moreover, we identified approximately 440 oilseed unique peptides in the cakes of all the analyzed oilseeds; the largest amounts were found in sesame (107 peptides), sunflower (100), pumpkin, hemp (42), rapeseed (36), and flax cake (35 peptides).

CONCLUSIONS

We provide novel information on unique / species-specific peptide markers that will extend the scope of testing the authenticity of a wide range of foods. The results of this peptide discovery experiment may further contribute to the development of targeted methods for the detection and quantification of oilseed proteins in processed foods, and thus to the improvement of food quality. © 2020 Society of Chemical Industry.

Effects of Microbial Transglutaminase on Technological, Rheological, and Microstructural Indicators of Minced Meat with the Addition of Plant Raw Materials

The aim of the study was to analyse the effects of transglutaminase on the physicochemical, technological, rheological, and microstructural indicators of minced meat with the addition of plant raw materials. The formulations of minced meat from beef trimming, hemp protein, and flax flour were optimized in terms of biological value and optimal content of essential amino acids. The addition of plant components in amounts greater than 18% caused an increase in the content of protein, fat, and ash in the minced samples. The rheological properties of minced meat samples without enzyme treatment changed depending on the proportion of plant raw materials. When the content of the flax flour was increased, the minimum ultimate shear stress and viscosity were observed, while the maximum values for these indicators were achieved in samples containing about 15% hemp protein, as well as in samples without plant additives. When adding transglutaminase to the formulation, increases in the ultimate shear stress and viscosity were proven for all combined minced samples. The combined minces, containing flax flour, had a more plastic structure and the lowest modulus of elasticity, while minces including 14% hemp protein or more than 87% meat components were identical to the control samples in terms of deformation and elasticity. In enzyme-treated minces, the plasticity of the samples reduced while density and elasticity increased. Transglutaminase treatment contributed to the formation of optimal technological properties of combined minces. Microstructural analysis showed the intermolecular bonds between protein particles in combined minced samples with the addition of enzymes. The research results have demonstrated the effectiveness of using transglutaminase in the composition of combined minced meat for the formation of a homogeneous and dense system with the necessary technological and rheological properties.

Identification of species-specific peptide markers in cold-pressed oils

In recent years, cold-pressed vegetable oils have become very popular on the global market. Therefore, new versatile methods with high sensitivity and specificity are needed to find and combat fraudulent practices. The objective of this study was to identify oilseed species-specific peptide markers, using proteomic techniques, for authentication of 10 cold-pressed oils. In total, over 380 proteins and 1050 peptides were detected in the samples. Among those peptides, 92 were found to be species-specific and unique to coconut, evening primrose, flax, hemp, milk thistle, nigella, pumpkin, rapeseed, sesame, and sunflower oilseed species. Most of the specific peptides were released from major seed storage proteins (11 globulins, 2S albumins), and oleosins. Additionally, the presence of allergenic proteins in the cold-pressed oils, including pumpkin Cuc ma 5, sunflower Hel a 3, and six sesame allergens (Ses i 1, Ses i 2, Ses i 3, Ses i 4, Ses i 6, and Ses i 7) was confirmed in this study. This study provides novel information on specific peptides that will help to monitor and verify the declared composition of cold-pressed oil as well as the presence of food allergens. This study can be useful in the era of widely used unlawful practices.

The seed of industrial hemp (Cannabis sativa L.): Nutritional Quality and Potential Functionality for Human Health and Nutrition

Hempseeds, the edible fruits of the Cannabis sativa L. plant, were initially considered a by-product of the hemp technical fibre industry. Nowadays, following the restorationing of the cultivation of C. sativa L. plants containing an amount of delta-9-tetrahydrocannabinol (THC) <0.3% or 0.2% (industrial hemp) there is a growing interest for the hempseeds production due to their high nutritional value and functional features. The goal of this review is to examine the scientific literature concerning the nutritional and functional properties of hempseeds. Furthermore, we revised the scientific literature regarding the potential use of hempseeds and their derivatives as a dietary supplement for the prevention and treatment of inflammatory and chronic-degenerative diseases on animal models and humans too. In the first part of the work, we provide information regarding the genetic, biochemical, and legislative aspects of this plant that are, in our opinion essential to understand the difference between “industrial” and “drug-type” hemp. In the final part of the review, the employment of hempseeds by the food industry as livestock feed supplement and as ingredient to enrich or fortify daily foods has also revised. Overall, this review intends to encourage further and comprehensive investigations about the adoption of hempseeds in the functional foods field.

Hemp (Cannabis sativa L.) Protein Hydrolysates Promote Anti-Inflammatory Response in Primary Human Monocytes

Hemp seeds have a wide variety of chemical compounds which present biological activity. Specifically, the focus on proteins and bioactive peptides are increasing as alternative sources of nutraceutical uses. In the literature, hemp protein products (HPPs) have reported antioxidant and anti-inflammatory properties. This study aimed to determine the inflammation-related modulatory effects of HPPs on lipopolysaccharide (LPS)-activated primary human monocytes. CD14⁺ cells were immunomagnetically isolated from buffy coats and the anti-inflammatory activity of hemp protein isolate (HPI) and hydrolysates (HPHs) was evaluated on LPS-stimulated human primary monocytes. The specific markers of inflammation, polarization, and chemoattraction were measured by RT-qPCR and ELISA assays. Our results showed that HPPs decreased the pro-inflammatory mediators (TNF-α, IL-1β, and IL-6) and increased the anti-inflammatory mediators (IL-10 and IL-4). In addition, M1 polarization marker gene expression (CCR7 and iNOS) was downregulated by HPPs and, M2 polarization marker gene expression (CD200R and MRC1) was upregulated. Finally, the mRNA expression of chemotaxis genes (CCR2 and CCL2) was downregulated by HPPs. In conclusion, this study suggests that HPPs may improve chronic inflammatory states and promote regenerative processes by reprogramming monocytes toward M2 polarization phenotype.

The Genomics of Cannabis and Its Close Relatives

Cannabis sativa L. is an important yet controversial plant with a long history of recreational, medicinal, industrial, and agricultural use, and together with its sister genus Humulus, it represents a group of plants with a myriad of academic, agricultural, pharmaceutical, industrial, and social interests. We have performed a meta-analysis of pooled published genomics data, andwe present a comprehensive literature review on the evolutionary history of Cannabis and Humulus, including medicinal and industrial applications. We demonstrate that current Cannabis genome assemblies are incomplete, with ∼10% missing, 10-25% unmapped, and 45S and 5S ribosomal DNA clusters as well as centromeres/satellite sequences not represented. These assemblies are also ordered at a low resolution, and their consensus quality clouds the accurate annotation of complete, partial, and pseudogenized gene copies. Considering the importance of genomics in the development of any crop, this analysis underlines the need for a coordinated effort to quantify the genetic and biochemical diversity of this species.

Neuroprotective protein hydrolysates from hemp (Cannabis sativa L.) seeds

Hemp (Cannabis sativa L.) seeds are well known for their potential use as a source of nutrients, fiber, and bioactive compounds. A hemp protein isolate, prepared from defatted hemp flour, was hydrolyzed by alcalase and flavourzyme under specific conditions. The resulting hydrolysates were evaluated for the selection of potentially bioactive hemp protein hydrolysates (HPHs) owing to their DPPH scavenging and ferric reducing antioxidant power activity. In vitro cell-free experiments led to the identification of two bioactive HPHs, HPH20A and HPH60A + 15AF, which were used at 50 and 100 μg mL-1 on BV-2 microglial cells in order to evaluate the anti-neuroinflammatory activities. Our results showed that HPH20A and HPH60A + 15AF down-regulated TNF-α, IL-1β, and IL-6 mRNA transcriptional levels in LPS-stimulated BV-2 microglial cells. In addition, HPH20A and HPH60A + 15AF up-regulated the gene expression of anti-inflammatory cytokine IL-10. This study suggests for the first time that HPHs may improve the neuroinflammatory and inflammatory states, supporting the nutraceutical value of hemp seeds.

Effect of heating on the digestibility of isolated hempseed (Cannabis sativa L.) protein and bioactivity of its pepsin-pancreatin digests

The objective was to investigate the effects of heat pretreatment and simulated gastrointestinal digestion on potential antioxidant, anticancer and anti-inflammatory activities of hempseed (Cannabis sativa L.) proteins. Unheated isolated hempseed protein (IHP) and its heated counterparts (100 °C, 15 min and 30 min, termed as HP15D and HP30D) were hydrolyzed sequentially with pepsin and pancreatin and analyzed for digestibility and bioactivity (antioxidant, anti-proliferative and anti-inflammatory properties). Heat pretreatment led to an increase of low molecular weight proteins and degree of hydrolysis, and decrease of concentration of soluble protein, which means heat pretreated can significantly improve the digestibility of IHP. Pepsin-pancreatin digests released from heat pretreated IHP possessed less antioxidant, antiproliferative and anti-inflammatory properties than digests from unheated IHP. In conclusion, heat pre-treatment improved the digestibility of IHP but the resulting digests from heated IHP had lower bioactivity.

Genipin-Aided Protein Cross-linking to Modify Structural and Rheological Properties of Emulsion-Filled Hempseed Protein Hydrogels

Genipin, a natural electrophilic cross-linker, was applied (5, 10, 20, and 30 mM) to modify hempseed protein isolate (HPI). Genipin treatments resulted in general losses of total sulfhydryls (up to 2.9 nmol/mg) and free amines (up to 77.3 nmol/mg). Surface hydrophobicity decreased by nearly 90% with 30 mM genipin, corresponding to similar tryptophan fluorescence quenching. The genipin treatment converted HPI into highly cross-linked polymers. Hydrogels formed with such polymers when also incorporated with hemp oil emulsions exhibited substantially enhanced gelling ability: up to 3.3- and 2.6-fold increases, respectively, in gel strength and gel elasticity over genipin-untreated protein. The genipin-modified composite gels also exhibited superior water-holding capacity. Microstructural analysis revealed a compact gel network filled with protein-coated oil globules that interacted intimately with the protein matrix when treated with genipin. Such gels remained readily digestible. Hence, genipin-treated hemp protein hydrogels show promise as functional food components.

A Multiple Protease Strategy to Optimise the Shotgun Proteomics of Mature Medicinal Cannabis Buds

Earlier this year we published a method article aimed at optimising protein extraction from mature buds of medicinal cannabis for trypsin-based shotgun proteomics (Vincent, D., et al. Molecules2019, 24, 659). We then developed a top-down proteomics (TDP) method (Vincent, D., et al. Proteomes2019, 7, 33). This follow-up study aims at optimising the digestion of medicinal cannabis proteins for identification purposes by bottom-up and middle-down proteomics (BUP and MDP). Four proteases, namely a mixture of trypsin/LysC, GluC, and chymotrypsin, which target different amino acids (AAs) and therefore are orthogonal and cleave proteins more or less frequently, were tested both on their own as well as sequentially or pooled, followed by nLC-MS/MS analyses of the peptide digests. Bovine serum albumin (BSA, 66 kDa) was used as a control of digestion efficiency. With this multiple protease strategy, BSA was reproducibly 97% sequenced, with peptides ranging from 0.7 to 6.4 kD containing 5 to 54 AA residues with 0 to 6 miscleavages. The proteome of mature apical buds from medicinal cannabis was explored more in depth with the identification of 27,123 peptides matching 494 unique accessions corresponding to 229 unique proteins from Cannabis sativa and close relatives, including 130 (57%) additional annotations when the list is compared to that of our previous BUP study (Vincent, D., et al. Molecules2019, 24, 659). Almost half of the medicinal cannabis proteins were identified with 100% sequence coverage, with peptides composed of 7 to 91 AA residues with up to 9 miscleavages and ranging from 0.6 to 10 kDa, thus falling into the MDP domain. Many post-translational modifications (PTMs) were identified, such as oxidation, phosphorylations, and N-terminus acetylations. This method will pave the way for deeper proteome exploration of the reproductive organs of medicinal cannabis, and therefore for molecular phenotyping within breeding programs.

Hemp (Cannabis sativa L.) Protein Extraction Conditions Affect Extraction Yield and Protein Quality

The purpose of this paper was to study the extraction conditions of hemp proteins from undelipidated press-cakes. The effects of different hydration conditions on protein recovery yield and polypeptide profile were evaluated: pH (2 to 12), ionic strength (0 to 500 mM NaCl) and press-cake/liquid weight ratio (2% to 22%). pH was the most impacting factor. At acidic pH (2 to 7) the extraction yields were low and quite constant (<7%), corresponding mainly to hemp albumins solubilization. The extraction of globulins started to increase significantly from pH 8, with protein extraction yield varying from 8.3% at pH 8 to 67.1% at pH 12 for a 10% press-cake/liquid weight ratio. The addition of NaCl in press-cake suspensions did not increase the total nitrogen content in aqueous extracts at alkaline pH while the lowest press-cake/liquid weight ratios (5% to 10%) were revealed optimal regarding protein recovery rate. The intense coloration observed on the aqueous extracts above pH 8 was assigned to solubilization and oxidation of phenolic compounds whose concentration increased about sevenfolds from pH 2 to 12. At the highest applied pH (11 to 12), the formation of covalent complexes between phenolic compounds and some hemp polypeptides was hypothesized. Aqueous extraction at strong alkaline pH (>9) without salt addition and respecting a 10% press-cake/liquid weight ratio should be retained to optimize protein extraction yield. However, further purification steps are required to evaluate the nutritional, organoleptic, and techno-functional properties of hemp proteins extracted in such conditions. PRACTICAL APPLICATION: The traditional extraction process of hemp proteins by alkaline solubilization and isoelectric precipitation, mostly from delipidated hemp press-cake, leads to limited quantity and poor solubility of extracted proteins, and data related to extraction conditions are insufficiently available to optimize this process. This article aims to find optimal hydration conditions (pH, ionic strength, press-cake to liquid ratio) for protein extraction from undelipidated hemp press-cake, allowing high protein recovery and preserving protein quality. The results obtained represent very useful data for developing an economically viable and sustainable extraction process of proteins from raw hemp press-cake.

Antiproliferative and antioxidant effect of polar hemp extracts (Cannabis sativa L., Fedora cv.) in human colorectal cell lines

Total phenolic content and antioxidant activity of polar extracts of edible resources from Fedora hemp cultivar (Cannabis sativa L.), namely seed, flour and oil, were evaluated. The main components in the polar extracts were identified using HPLC-DAD and HPLC-ESI-MS/MS. As expected, the molecular profile of components from seeds and flour was strictly similar, dominated by N-trans-caffeoyltyramine. The profile of oil polar extracts contained hydroxycinnamic acid derivatives and cannabinoids at lower extent. While the extracts from hemp seed and flour did not interfere with growth of Caco-2 and HT-29 cell, the one from oil (150 µg/mL) significantly reduced cell viability after 24 h of treatment. This effect was associated with the activation of apoptotic cell death and was independent from the antioxidant capacity of the oil polar extract. Notably, HT-29 cells differentiated with sodium butyrate were not sensitive to the cytotoxic effect of the oil extract.

Phytochemical and Ecological Analysis of Two Varieties of Hemp (Cannabis sativa L.) Grown in a Mountain Environment of Italian Alps

Hemp (Cannabis sativa L.) is a multifunctional crop that is capable of prompt environmental adaptation. In this study, a monoecious cultivar (Futura 75) and a dioecious one (Finola) were tested in a mountain area in Valsaviore (Rhaetian Alps, Italy; elevation: 1,100 m a.s.l.) during the growing season 2018. Phytochemical behavior was evaluated by different analytical approaches: HPLC-high-resolution mass spectrometry, SDS-PAGE LC-MS/MS, HS-SPME GC-MS, and GC-FID in order to obtain complete profile of two varieties cultivated in altitude. CSR functional strategy used for ecological evaluation revealed that both genotypes are mainly competitors, although Finola is more stress tolerator (C:S:R = 57:26:17%) than Futura (C:S:R = 69:15:16%). The Finola inflorescences were characterized by higher quantities of β-ocimene and α-terpinolene, while α- and ß-pinene accompanied by extremely high ß-myrcene were found as predominant in Futura. Both varieties were rich in sesquiterpenes (45 recognized) among which trans-caryophyllene and α-humulene were the most abundant. Total tetrahydrocannabinol level was lower than 0.1%, while the most abundant cannabinoid was cannabidiolic acid (CBDA): 2.3% found in Finola vs. 2.7% revealed for Futura. The level of corresponding neutral form, cannabidiol, varied drastically: 0.27% (Finola) vs. 0.056% (Futura). Finola showed the unique cannabinoid profile with unexpectedly high cannabidivarin, 2-fold higher that corresponding acidic analogue, whereas the particularity of Futura 75 was the occurrence of cannabigerolic acid (CBGA) in the quantities that was double than those exposed for Finola. The seeds from both chemovars proved to be rich in polyunsaturated fatty acids, and Finola showed a higher ratio ω6/ω3. No difference was found in the protein content, and the SDS-PAGE profile was similar. The most abundant protein was edestin, followed by heat shock protein 70, ß-conglycinin, and vicilin. In conclusion, comprehensive phytochemical and ecological study of two fiber-type varieties cultivated in Italian Alps displayed specific, legal, and safe cannabinoids profile, followed by particular terpene composition, polyunsaturated fatty acids content, and favorable protein profile. This postulates that geographical provenience of hemp should be considered in selecting a variety that would be suitable for a specific end-use nutraceutical application.