1,721,064 research outputs found
Black soldier fly (Hermetia illucens L.) whole and fractionated larvae: In vitro protein digestibility and effect of lipid and chitin removal
No full textProtein quality, which can be defined by amino acid profile and protein digestibility, is of paramount importance when assessing a novel protein source. As the presence of chitin might impair insect protein digestion, and as there is little to no clarity as to how different insect fractions influence the overall protein digestibility, this study aimed at assessing the influence of lipids and chitin removal on the protein digestibility of black soldier fly larvae. The samples underwent an in vitro simulated gastro-intestinal digestion following the INFOGEST method, commonly used for humans, and both undigested matrices and digesta were characterized by means of amino acid composition, SDS-PAGE gel electrophoresis, and proteomic/peptidomic approaches. Protein solubilization, degree of hydrolysis (DH%) after digestion, and digestible indispensable amino acid (DIAA) contents were also determined. The results highlighted that the presence of chitin hindered protein digestion, as expected: in fact, the protein isolate showed the highest solubilized protein (84.0%), DH% (61.1%), and number of peptides and proteins detected by high resolution mass spectrometry (64 and 16, respectively), while the chitin-rich fraction the lowest (38.4% solubilized protein, 41.2% DH%, 37 peptides and 6 proteins detected, respectively). Additionally, the chitin-rich fraction had the lowest DIAAS. Interestingly, the preferred C-terminal cleavage sites for all samples were in line with the specificity of the enzymes used, meaning that insect proteins, compared to other matrices, do not change the enzymatic behavior in terms of their specificity
Killing method affects the browning and the quality of the protein fraction of Black Soldier Fly (Hermetia illucens) prepupae: a metabolomics and proteomic insight
No full textInsects are being explored as novel protein sources in order to overcome the future food demands connected to world growing population. Insects for food/feed uses are currently slowly killed through freezing by most insect rearing companies, and typically, enzymatic browning takes place in the insect proteins fractions. However, very little is known about the influence of these enzymatic reactions on the protein physical, chemical, nutritional and technological properties. In this work a metabolomics and proteomic study was conducted on Black Soldier Fly (Hermetia illucens) prepupae, killed by two different methods: freezing (commonly used), and blanching (with the aim to inhibit the enzymatic activities). Proton nuclear magnetic resonance (H-1 NMR) metabolomics demonstrated that slow killing method by freezing, compared with blanching, elicits the activation of several enzymatic pathways, among them melanisation with tyrosine consumption, energetic metabolism and lipolysis. These metabolic changes have an impact also on protein nutritional quality, with a loss of cysteine and lysine, likely involved in the process of melanisation and enzymatic browning. A strong effect was also observed on protein extractability: proteins from prepupae killed by blanching were found to be more extractable in milder conditions by chemical methods, and more prone to enzymatic digestion (97% of proteins released in solution upon proteolysis) than proteins from prepupae killed by freezing. All these data indicate that killing by blanching inhibits the browning reaction and other enzymatic changes occurring during slow killing by freezing, increasing the extractability of proteins in aqueous solutions, avoiding essential amino acid loss, and improving enzymatic digestibility
Evaluating physical pre-treatment methods for improving insect chitin hydrolysis using Streptomyces griseus chitinase
No full textChitin and particularly its derivatives, chitosan and chitoligosaccharides (COS), are gaining interest as highly functional biopolymers with many applications. Chitin, the main component of the exoskeleton of crustaceans and insects, has a resistant structure that makes access to chitinolytic enzymes extremely difficult, thus limiting the possibility of obtaining COS. Therefore, several pre-treatments have been investigated to interfere with the crystalline organisation of chitin and improve its enzymatic hydrolysis. This study tested different physical pre-treatment methods (ultrasonication, mechanochemical milling, and the use of pulsed electric fields) on different insect species (Hermetia illucens, Acheta domesticus, and Tenebrio molitor) compared to shrimp shells, aiming to intensify COS formation through the hydrolysis of the whole insects with chitinase from Streptomyces griseus. The findings of this study highlighted the importance of pre-treatments in enhancing the enzymatic hydrolysis of chitin and suggested the potential of insect-derived chitin as a sustainable source for COS production. In particular, different insect species produced different amounts of N-acetylglucosamine and N,N’-diacetylglucosamine, and mechanochemical pre-treatment on Hermetia illucens was the most effective. Additionally, this insect also had a lower degree of acetylation, calculated by 1H NMR, than the other species, indicating a possible influence on enzyme activity
HS-SPME/GC-MS and chemometrics for the classification of Balsamic Vinegars of Modena of different maturation and ageing
No full textHead space solid-phase microextraction (HS-SPME) coupled with GC-MS analysis has been applied for the determination of the characteristic volatile profile of Balsamic Vinegar of Modena (BVM) with the aim to distinguish the less matured products (matured in wooden barrels for at least 60 days) from the aged ones (aged in wooden barrels for at least 3 years). Coupling the HS-SPME/GC-MS analysis data with multivariate statistical techniques, such as Principal Components Analysis (PCA) and Classification Trees (CT), it has been possible to classify BVMs on the basis of different maturation and ageing. A matured BVM presents an aromatic profile characterised by high contents of 3-methyl-1-butanol, 4-ethyl-phenol, and 3-methyl-1-butanol acetate, while an aged BVM is characterised by a prevalence of ethyl acetate, ethyl acetoacetate, furans, 2,3-butanediol and 2,3-butanediol acetate. This work represents a first attempt to classify Balsamic Vinegars of Modena on the basis of their maturation and ageing. (C) 2010 Elsevier Ltd. All rights reserved
Chiral markers: a useful tool for the quality control of cocoa beans and related products.
No full textBlack soldier fly as a New chitin source: Extraction, purification and molecular/structural characterization
Full text linkBlack Soldier Fly (BSF) represents a potential chitin source that has not been fully explored in terms of characterization, extraction, and purification. In this study, different chemical and enzymatic protocols with or without pre-treatment (ultrasonication and mechanochemical milling) for chitin extraction were tested. Chitin was then accurately quantified and characterized from a molecular and structural point of view by UPLC-MS, XRD, and ESEM, and compared with chitin from shrimp shells. BSF chitin was more recalcitrant than shrimp chitin during extraction and purification, due to the strong binding of chitin to proteins. Indeed, the purity of shrimp chitin was 88.3g/100g of extract, while BSF chitin purity was 47.6–79.9g/100g. Furthermore, the chitin-bound proteins had a defined amino acid composition; their binding was also confirmed by structural characterization. Therefore, the efficiency of each step of the extraction process needs to be critically evaluated to adapt the methods used for crustaceans to insect biomass
Determination of cyclopropenoid fatty acids in ewe milk fat by GC-MS after intravenous administration of sterculic acid
No full textCyclopropenoid fatty acids (CPEFA), found in oilseeds from Malvaceae and Sterculiaceae, have been shown to interfere with the endogenous synthesis of several bioactive lipids of dairy fat, such as cis-9, trans-11 18:2 and cis-9 18:1, by inhibiting Δ9-desaturase. No previous study has reported the presence of sterculic acid in animal fat and its incorporation in tissues after its administration, due to the lack of a proper methodology. In the present research, a GC-MS method based on cold base derivatization to fatty acids methylesters was developed to determine CPEFA in ewe milk triglycerides, after infusing sterculic acid (0.5 g/day) to six lactating ewes. An alternative derivatization based on silanyzation followed by GC-MS analysis was also tested, showing its possible applicability when CPEFA are present in the form of free fatty acids. Sterculic acid was detected in ewe milk triglycerides, demonstrating its incorporation from the bloodstream into milk by the mammary gland. The mean transfer rate represented 8.0 ± 1.0% of the daily dose. This study provides, for the first time, the presence of sterculic acid in milk fat, supporting the importance of understanding its occurrence in vivo and encouraging further research to determine whether it can be present in foods, such as dairy products, obtained under practical farming conditions
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