scholarly journals Valorization of Aquaculture By-Products of Salmonids to Produce Enzymatic Hydrolysates: Process Optimization, Chemical Characterization and Evaluation of Bioactives

Marine Drugs ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. 676 ◽  
Author(s):  
José Antonio Vázquez ◽  
Carmen G. Sotelo ◽  
Noelia Sanz ◽  
Ricardo I. Pérez-Martín ◽  
Isabel Rodríguez-Amado ◽  
...  

In the present manuscript, various by-products (heads, trimmings, and frames) generated from salmonids (rainbow trout and salmon) processing were evaluated as substrates for the production of fish protein hydrolysates (FPHs), potentially adequate as protein ingredients of aquaculture feeds. Initially, enzymatic conditions of hydrolysis were optimized using second order rotatable designs and multivariable statistical analysis. The optimal conditions for the Alcalase hydrolysis of heads were 0.1% (v/w) of enzyme concentration, pH 8.27, 56.2°C, ratio (Solid:Liquid = 1:1), 3 h of hydrolysis, and agitation of 200 rpm for rainbow trout and 0.2% (v/w) of enzyme, pH 8.98, 64.2 °C, 200 rpm, 3 h of hydrolysis, and S:L = 1:1 for salmon. These conditions obtained at 100 mL-reactor scale were then validated at 5L-reactor scale. The hydrolytic capacity of Alcalase and the protein quality of FPHs were excellent in terms of digestion of wastes (Vdig > 84%), high degrees of hydrolysis (Hm > 30%), high concentration of soluble protein (Prs > 48 g/L), good balance of amino acids, and almost full in vitro digestibility (Dig > 93%). Fish oils were recovered from wastes jointly with FPHs and bioactive properties of hydrolysates (antioxidant and antihypertensive) were also determined. The salmon FPHs from trimmings + frames (TF) showed the higher protein content in comparison to the rest of FPHs from salmonids. Average molecular weights of salmonid-FPHs ranged from 1.4 to 2.0 kDa and the peptide sizes distribution indicated that hydrolysates of rainbow trout heads and salmon TF led to the highest percentages of small peptides (0–500 Da).

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 703
Author(s):  
Severino Zara ◽  
Giacomo L. Petretto ◽  
Alberto Mannu ◽  
Giacomo Zara ◽  
Marilena Budroni ◽  
...  

The production of saffron spice generates large quantities of plant by-products: over 90% of the plant material collected is discarded, and a consideration fraction of this waste is plant stamens. This work investigated the chemical composition and the antimicrobial activities of the non-polar fraction extracted from four different saffron flower stamens. The chemical composition of ethereal extracts of the saffron stamens was qualitatively assessed by means of gas–chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses. These analyses revealed ethereal extracts to possess a high polyunsaturated fatty acid content. In vitro antibacterial activity of stamen extracts showed no large differences between Gram-positive and Gram-negative bacteria in terms of minimal inhibitory concentration (MIC). In food matrix microbial analysis of the bacterial strains belonging to the main foodborne pathogen species, including Staphylococcus aureus DSM 20231, Escherichia coli DSM 30083, and Listeria monocytogenes DSM 20600, using low-fat UHT milk, revealed a statistically significant reduction in the number of cells (particularly for E. coli and S. aureus with a complete elimination of the population of the two target bacteria following incubation in diethyl ether extracts of saffron stamen (DES) at high concentrations tested, both at 37 °C and 6 °C (for 48 h and 7 days, respectively). A synergic effect was observed when the pathogens were incubated at 6 °C with DES. This work shows these by-products to be excellent sources of bioactive compounds, which could be exploited in high-added-value products, such as food, cosmetics, and drugs.


2020 ◽  
Vol 60 (5) ◽  
pp. 659 ◽  
Author(s):  
Gamonmas Dagaew ◽  
Anusorn Cherdthong ◽  
Metha Wanapat ◽  
Pin Chanjula

Context Feeding ruminants with fresh cassava roots (FCR) is limited because they have a high concentration of hydrocyanic acid (HCN). Thus, it was hypothesised that receiving a feed block containing high sulfur (FBS) would reduce hydrocyanic acid (HCN) in FCR and improve rumen fermentation and nutrient digestibility in animals. Aims The goal of the present work was to study the influence of the ratio of FCR to rice straw (RS) together with FBS on kinetics of gas production, HCN concentration, fermentation characteristics and nutrient digestibility, using in vitro technique. Methods The experimental design was a 4 × 2 factorial arrangement in a completely randomised design, with three replications per treatment. Factor A was the FCR to RS ratio, which was 100:0, 60:40, 40:60 or 0:100. Factor B was sulfur, which was provided as two concentrations in FBS (2% and 4% DM). Gas production was recorded after incubation, at 0, 0.5, 1, 2, 4, 6, 8, 12, 18, 24, 48, 72 and 96 h. Fermentation liquor was collected and determined for kinetics of gas production, HCN concentration, fermentation characteristics and nutrient digestibility. Key results Cassava root to RS ratio influenced the cumulative gas production after 96 h. Inclusion of sulfur in the FBS at 4% increased the cumulative gas production, when compared with inclusion at 2%. The gas production from degradable fraction (b) and the rate of gas production (c) were significantly different among the treatments with different FCR:RS ratios, whereas there was no difference between using 2% and 4% sulfur in the FBS. The HCN concentration in fermentation liquor increased with an increasing proportion of FCR. Furthermore, inclusion of sulfur in the feed block at 4% reduced HCN concentration by 42.8%, when compared with inclusion at 2% (P < 0.05). Ammonia-nitrogen concentration was significantly different among the FCR:RS-ratio treatments and was reduced when the proportion of FCR was decreased (P < 0.05). In vitro digestibility was significantly increased with an increasing proportion of FCR. Increasing the proportion of FCR with 4% of sulfur in the FBS significantly increased in vitro DM digestibility, compared with 2% sulfur. Increasing the FCR:RS ratio with 4% of sulfur in the FBS increased the proportion of propionic acid (P < 0.05). Conclusions Using a high FCR:RS ratio (100:0 or 60:40) with 4% sulfur in the FBS enhanced kinetics of gas production, propionic molar proportion, nutrient digestibility, and HCN detoxification by rumen microbes in an in vitro trial. Implications An in vivo study should be encouraged to verify the results and obtain more data.


2013 ◽  
pp. 313-317 ◽  
Author(s):  
J. Fuentes-Rodriguez ◽  
A. Abrego-Garcia ◽  
F. Ruiz-Zarate ◽  
G. Montero-Almora ◽  
M. Torres Hernandez ◽  
...  

2021 ◽  
Author(s):  
Shahram Shirmohammadi ◽  
Akbar Taghizadeh ◽  
Hamid Paya ◽  
Arash Javanmard ◽  
Soheila Abachi ◽  
...  

Abstract Over the past decades, the agro-industrial by-products (AIBP) has received considerable attention. With this motivation, the aim of this study was to investigate the effect of AIBP as a source of non-fiber carbohydrates on biogas production kinetic, methane emission and fermentation characteristics. Experimental treatments were (1) Sugar beet pulp (SBP) (control), (2) Apple pomace (AP), (3) Orange pulp (OP, (4) 33% AP + 66% OP, (5) 50% AP + 50% OP and (6) 66% AP + 33%OP. For this work, we analyzed the data collected from the kinetics of digestion through biogas production, ex-vivo methane emission, in-vitro digestibility of dry matter and fermentation parameters. Field emission scanning electron microscope was used to show the nano structural differences of the AIBPs. Our results demonstrated the significant differences of the crude protein among the treatments (P < 0.05). Biogas production and methane emission were significantly higher in SBP and OP treatments (P < 0.05). The most eminent and the lowest amounts of acetate were observed for AP and OP (61.84 mmol/L, 58.15 mmol/L), respectively. More broken edges were obvious in OP images. particle size was rather smaller in SBP. Images of AP showed a sleek surface which may act as a shield preventing more digestion. Overall, beside reducing environmental contamination by AIBP, our results showed a positive effect of AIBPs on degradation and biogas kinetics, methane emission and in vitro fermentation parameters describing that they can be used as a good source of non-fiber energy sources.


1994 ◽  
Vol 71 (1) ◽  
pp. 195-203 ◽  
Author(s):  
K. J. Loechner ◽  
L. K. Kaczmarek

1. In response to brief stimulation of an afferent input the bag cell neurons of Aplysia depolarize by 15-20 mV and generate an afterdischarge that, in vitro, lasts for approximately 30 min. During the discharge these neurons secrete three small peptides [bag cell peptides (BCPs)], Ala-Pro-Arg-Leu-Arg-Phe-Tyr-Ser-Leu (alpha-BCP), Arg-Leu-Arg-Phe-His (beta-BCP), and Arg-Leu-Arg-Phe-Asp (gamma-BCP), that share a common core sequence and that have electrophysiological effects on the bag cell neurons themselves. We have now studied the action of these three peptides on bag cell neurons isolated in culture. All three peptides were found to be capable of producing a depolarization of these cells. 2. The ability of alpha-, beta-, and gamma-BCP to induce a depolarization in isolated bag cell neurons exhibits a seasonal variability. The response to the peptides is maximal from early summer through late fall and parallels the frequency of egg-laying in vivo. 3. The depolarization induced by alpha-, beta-, and gamma-BCP desensitizes with repeated application of peptide. Desensitization of the response to one peptide does not, however, prevent the response to application of one of the other two peptides. This suggests that separate autoreceptor populations exist for alpha-, beta-, and gamma-BCP. 4. As reported previously, desensitization of the depolarizing response to the peptides was also observed after preincubation of intact clusters of bag cell neurons with a high concentration of all three peptides.(ABSTRACT TRUNCATED AT 250 WORDS)


Author(s):  
Giorgia Meineri ◽  
Pier Giorgio Peiretti ◽  
Sonia Tassone ◽  
Alessia Candellone ◽  
Erica Longato ◽  
...  

The objectives of this study were: (a) to evaluate the effect of inclusion of mechanically separated chicken meat (MSCM) in dry dog food on fatty acid profile, in vivo and in vitro digestibility, and palatability as compared with dry dog food containing meat by-products (MBP); (b) to determine, whether or not, the inclusion of the one or the other ingredient changes the microbiology and the storage quality of the two food products; (c) to propose a new system (DaisyII Incubator) to measure the in vitro digestibility of the two products. Their similar chemical composition notwithstanding, the MSCM product had lower palatability but better nutritional quality (with higher polyunsaturated fatty acid [PUFA] content and lower saturated fatty acid [SFA] content) than the MBP product. Microbiological risk assessment showed no microbiological hazards for either product. After 6 months storage, polyamine values were found to be higher in the MSCM than in the MBP. Finally, the DaisyII Incubator proved a valid instrument for the study of in vitro digestibility also for dogs; since it provided data simply, quickly with less variability and cost than obtained with in vivo trials, it could represent the future for pet food digestibility studies. Our results indicate that inclusion of MSCM or MBP as the main protein ingredient in extruded pet food may be used advantageously in product formulations.


Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1503
Author(s):  
Jesus Valcarcel ◽  
Noelia Sanz ◽  
José Antonio Vázquez

Valorization of seabass and seabream by-products is becoming increasingly relevant, as marketing of these species moves from selling whole fish to filleting for convenience products. With this aim, we optimized for the first time the production of fish protein hydrolysates (FPH) by enzymatic hydrolysis from filleting by-products of these commercially relevant aquaculture species, isolating fish oil at the same time. On the whole, both fish yielded similar amounts of protein, but frames and trimmings (FT) were the best source, followed by heads and viscera. In vitro antioxidant and antihypertensive activities showed similar figures for both species, placing FPHs from FT as the most active. Molecular weights ranged from 1381 to 2023 Da, corresponding to the lowest values of FT, in line with the higher hydrolysis degrees observed. All FPHs reached high digestibility (>86%) and displayed an excellent amino acid profile in terms of essential amino acids and flavor, making them suitable as food additives and supplements.


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