Dynamic rheology and endothermic transitions of proteins recovered from chicken-meat processing by-products using isoelectric solubilization/precipitation and addition of TiO2

Effects of different hydrocolloids on the 3D printing and thermal stability of chicken paste

This study investigated the effect of different hydrocolloids on the improvement of the printability and post-processing stability of minced chicken meat, each hydrocolloid was prepared with 1 % formulation and compared with the control. The effects of these hydrocolloids on the rheological properties of chicken mince and complex model printing capability were explored separately, while the cooking loss and microstructure changes of the samples before and after heating were analyzed. The results showed that the chicken mince gel containing carrageenan was more suitable for printing, increased the yield stress and apparent viscosity of the samples, and the printing process was easier to mold. In addition, carrageenan increased the hardness of the samples, and the microstructures were compact and changed little during the heating process, and the water was locked in the gel matrix, reducing shape changes during the heating process. The use of hydrocolloids improves the stability of post-processing of chicken 3D printing.

Effect of vegetable oils on the thermal gel properties of PSE-like chicken breast meat protein isolate-based emulsion gels

To enhance the gel properties of PSE (pale, soft, and exudative)-like chicken meat protein isolate (PPI), the effect of peanut, corn, soybean, and sunflower oils on the gel properties of PPI emulsion gels was investigated. Vegetable oils improved emulsion stability and gel strength and enhanced viscosity and elasticity. The gel strength of the PPI-sunflower oil emulsion gel increased by 163.30 %. The thermal denaturation temperature and enthalpy values were increased. They decreased the particle size of PPI emulsion (P < 0.05) and changed the three-dimensional network structure of PPI emulsion gels from reticular to sheet with a smooth surface and pore-reduced lamellar. They elevated the content of immobile water PPI emulsion gels, decreased the α-helix and β-turn, and increased the β-sheet and random coil. Vegetable oil improved the gel properties of PPI in the following order: sunflower oil > soybean oil > corn oil ≈ peanut oil > control group.

Protein and Long-Chain n-3 Polyunsaturated Fatty Acids Recovered from Herring Brines upon Flocculation and Flotation-A Case Study

A novel integrated process for recovery of protein-enriched biomasses from 5% presalting brines and spice brines of herring (Clupea harengus) was investigated by combining carrageenan- and/or acid-driven flocculation (F) plus dissolved air flotation (DAF). The F-DAF technique with carrageenan resulted in protein and lipid recoveries from 5% presalting brine of 78 and 38%, respectively. Without flocculation or with only acidification, protein and lipid recoveries in DAF were only 13 and 10%, respectively. Low protein and lipid recoveries, 8-12 and 1.8-8.2%, respectively, were also obtained when spice brine was subjected to only acidification and DAF. The protein content in dry biomasses from 5% presalting brine and spice brine was 36-43 and 13-16%, respectively. The corresponding lipid levels were 23-31 and 9-18%, respectively, with ash levels of 11-20 and 38-45%, respectively. Biomass proteins contained ≤45% essential amino acids, and the lipids had ≤16% long-chain n-3 polyunsaturated fatty acids. Freeze-dried spice brine biomasses were characterized by anchovy- and spice-related sensory attributes. 5% presalting brine biomasses were connected to fish and seafood attributes and showed gel forming capacity. The outlined F-DAF recovery system can thus recover both nutrients and interesting flavors from the herring process waters, which are currently lost from the food chain.

Analysis of the Food Loss and Waste Valorisation of Animal By-Products from the Retail Sector

The meat industry generates a large amount of animal by-products not only derived from the slaughter process but also due to the losses and waste of meat products along the supply chain, contributing to the world’s food loss and waste problem. Yearly, 1.7 Mt of meat in the European retail sector and 20% of meat for consumption is wasted in this sector of the supply chain. Therefore, the aim of this paper was to find and evaluate alternatives for the valorisation of agri-food residues, more specifically the meat waste from the food retail sector, through a technological perspective. Thus, we delve into the industrial processes already implemented and the emerging procedures that use muscle, bones and fats by-products from poultry, cattle and pork as the main raw materials in order to identify and characterise them. The results indicate that in addition to the current destinations—landfill, incineration and the rendering process—these animal by-products can be incorporated in the production of biodiesel, food formulations, pharmaceuticals, fertilisers and biogas through an industrial symbiosis approach. Consequently, the several valorisation processes and procedures identified not only suggest an increase in concern about the impacts of the disposal of these materials, but also highlight the potential associated with the use of animal by-products as raw material to obtain added-value products.

Nano Filling Effect of Nonmeat Protein Emulsion on the Rheological Property of Myofibrillar Protein Gel

Incorporation of vegetable oils through pre-emulsification has received notable attention for delivering polyunsaturated fatty acids to emulsified-type meat products. The two important influencing factors of the rheological property of composite myofibrillar protein (MP) gel are emulsion droplet size and active or inactive interaction between interface and meat proteins. Incorporation of nonmeat protein emulsion (2% protein (w/w), egg-white protein isolate (EPI), porcine plasma protein (PPP), or sodium caseinate (SC)) with different droplet sizes (nano or macro) to a model of 2% MP gel was investigated in this research. The results of drop size measurement showed that 15,000 psi homogenizing could decrease the diameter of emulsion drop from macro- to nanoscale in the range of 324.4−734.5 nm. Active fillers (PPP and EPI emulsions) with nanodroplet size did not influence the viscosity of emulsion-filled composite cold sols but caused positive filling effects on the MP gel matrix after heating, as evidenced by the density microstructure. PPP and EPI nano-emulsion-filled composite MP had a significant high storage modulus enforcement effect, which reached nearly eight times those of other treatments (p < 0.05). Similarly, the results of thermal scanning rheology and a large-deformation mechanical test showed that PPP and EPI emulsions with nanoscale droplets, other than macroscale, had the highest gel strength of heat-induced emulsion-filled composite MP gel (p < 0.05). Overall, these findings will be helpful for selecting the correct pre-emulsified protein and designing the textural properties of foods.

Physicochemical characteristics of surimi-like material made from the muscle tissues of freshwater mussels (Sinanodonta woodiana Lea, 1834)

The aim of the study was to determine selected characteristics of surimi-like material (SLM) made from the muscle tissues of Sinanodonta woodiana (Lea, 1834) freshwater mussels. The research material consisted of unwashed mussel muscle homogenate as the control sample—C, mussel muscle tissue twice washed with water (SLM-W) and sample washed with NaCl at a concentration of 0.169 mol/L as well as water (SLM–S). A raw control sample and surimi like-materials were analysed using the SDS-PAGE technique. They were also tested using the DMTA method (dynamic mechanical thermal analysis) while heating the samples up to 80 °C and cooling to 20 °C. The thermal drip and texture of gels after heating (75 °C, 30 min) were also determined. The washing procedure had a significant impact on the protein composition of the SLMs. A significantly (p < 0.05) higher percentage of proteins with molecular weights of 270–273 kDa and 105–110 kDa (corresponding to specific filamin isoforms), as well as 42–43 kDa (corresponding to actin), were found in the SLMs compared to sample C. Ccorrelation analysis confirmed a strong positive relationship between the percentage share of the above proteins and the values of the elasticity modulus (r ≥ 0.84) and firmness (r ≥ 0.88) of SLM gels. The SLM-S sample was characterised by the lowest significant (p < 0.05) thermal drip values. During heating, the rheological traits of all samples changed at two stages: from 20 to 50 °C and over 50 °C. The highest dynamics of variation in the elasticity modulus (G′) value were noticed at temperatures exceeding 50 °C in all samples. The G′ values in the SLM samples were significantly greater than the values in sample C. The analysis revealed a strong correlation (r ≥ 0.81) between the determinants of the texture of the SLM samples and their rheological parameters. Sample SLM-W was the one with the highest firmness and elasticity values. The analysis showed that the textural properties of the SLM samples mainly resulted from the reaction of spatial matrices to mechanical interactions.

Effect of laver powder on textual, rheological properties and water distribution of squid (Dosidicus gigas) surimi gel

In order to ameliorate the gel quality of Dosidicus gigas surimi, the effects of laver powder on gel properties, rheological properties, and water-holding capacity (WHC) were investigated. Results indicated that the addition of laver powder could significantly increase the hardness, chewiness, and breaking force of surimi gels. However, the texture indexes and gel strength began to decline when additional amount exceeded 0.6%. Rheological results demonstrated that the addition of laver powder increased the storage modulus (G') and viscosity of surimi, prolonged protein denaturation temperature in surimi gels. Moreover, the WHC of surimi gel was improved with the increase of laver powder. Further analyses in low-field nuclear magnetic resonance revealed that laver powder could shorten the transverse relaxation time, enhanced the combination with water, and altered the distribution of different water categories. The proportion of bound water and immobilized water reached its maximum and minimum at 0.6% of laver powder, respectively. Correlation analyses showed that WHC of surimi gel was negatively correlated well with the proportion of loose-bound water, but positively correlated with the strong-bound water and free water. In conclusion, the results supported that 0.6% was the optimal additional amount of laver powder for the squid-based surimi production based on the current ingredients of surimi products.

Sustainability of food waste biorefinery: A review on valorisation pathways, techno-economic constraints, and environmental assessment

The need to increase circularity of industrial systems to address limited resources availability and climate change has triggered the development of the food waste biorefinery concept. However, for the development of future sustainable industrial processes focused on the valorisation of food waste, critical aspects such as (i) the technical feasibility of the processes at industrial scale, (ii) the analysis of their techno-economic potential, including available quantities of waste, and (iii) a life cycle-based environmental assessment of benefits and burdens need to be considered. The goal of this review is to provide an overview of food waste valorisation pathways and to analyse to which extent these aspects have been considered in the literature. Although a plethora of food waste valorisation pathways exist, they are mainly developed at lab-scale. Further research is necessary to assess upscaled performance, feedstock security, and economic and environmental assessment of food waste valorisation processes.

Anaerobic co-digestion of sewage sludge with cellulose, protein, and lipids: Role of rheology and digestibility

Rheology is known to have an impact on the performance of digesters, but the effect of additional substrates (co-digestion) is poorly understood. The main objective of this study was to investigate the effects of the addition of cellulose, protein and lipids to substrates on the rheological behaviour and biogas production of the mixture of primary sludge (PS) and waste-activated sludge (WAS) in a batch system. A mixture of PS and WAS to form the main substrate was anaerobically co-digested with different types of organic matter (cellulose, protein and lipids) as co-substrates at different co-substrate to main substrate ratios of 2-8 (wt%) under mesophilic conditions and below ammonia inhibition levels. Yield stress (τ_y) and the flow consistency index (k) of the combined feed in the case of cellulose and protein were significantly dependent on the amount of co-substrate added, while there was an insignificant impact on these properties when lipids were added. Cellulose significantly increased τ_y and k in the feed, which resulted in poor fluidity and the improper homogenisation of the digester content, and consequently decreased the biogas yield. In contrast, the biogas yield was improved through the addition of 2% to 6% protein despite an increase in τ_y and k of the feed, but the methane yield decreased at 7% and 8% levels of protein concentration. This observation indicates that the threshold for τ_y and k of the digester media depends on the organic nature and digestibility of the substrate. There was no significant impact on the flow properties of the initial mixture when lipids were added, and their addition increased the biogas yield. A first-order kinetic reaction model was used for predicting the yield of methane from these digesters. The rate constant values revealed an increasing trend, with the highest for protein then lipids then cellulose.

Synergistic Gelation Effects in Surimi Mixtures Composed of Nemipterus virgatus and Hypophthalmichtys molitrix

Mixtures of marine fish surimi and freshwater fish surimi might have synergistic gelation effects under certain conditions. Here, various mixtures of Nemipterus virgatus surimi and Hypophthalmichtys molitrix surimi were analyzed, with respect to gelation characteristics, rheological properties, protein conformations, and microstructure. When the ratio of N. virgatus surimi to H. molitrix surimi was 3:1, gel strength was increased by 3.08% and 92.13%, while cooking loss was reduced by 7.64% and 33.94%, as compared to pure N. virgatus surimi and pure H. molitrix surimi, respectively. In the mixed surimi as compared to the pure surimi, brightness and whiteness were improved, while water holding capacity, the elasticity modulus (G'), and the β-sheet content were increased. Three-dimensional (3D) network structure of the mixed surimi gel was more compact and uniform than that of either pure surimi gel. In a word, the elasticity modulus and β-sheet content of mixtures surimi were significantly increased, and the 3D structure was more compact and uniform; all these led to synergistic gelation effects in surimi mixtures composed of N. virgatus and H. molitrix. PRACTICAL APPLICATION: With the accelerated pace of life, the demand quantity of surimi products has increased year by year, but the main raw materials of marine fish resources are increasingly scarce. On the contrary, freshwater fish that can be used for surimi processing resources are very rich, and the price of them is low. Gel properties of freshwater fish surimi is worse than marine fish surimi, and how to improve it is one of the bottlenecks in the development of freshwater fish surimi. We and others have been found that the blended surimi from freshwater fish with marine fish could produce gel synergies under the proper conditions. So, Nemipterus virgatus (marine fish) surimi and Hypophthalmichtys molitrix (freshwater fish) surimi were used as raw materials, and the synergistic effects of the mixed surimi were explored.

Rheological characterisation of biologically treated and non-treated putrescible food waste

Food waste is gaining increasing attention worldwide due to growing concerns over its environmental and economic costs. Understanding the rheological behaviour of food waste is critical for effective processing so rheological measurements were carried out for different food waste compositions at 25, 35 and 45 °C. Food waste samples of various origins (carbohydrates, vegetables & fruits, and meat), anaerobically digested and diluted samples were used in this study. The results showed that food waste exhibits shear-thinning flow behaviour and viscosity of food waste is a function of temperature and composition. The composition of food waste affected the flow properties. Viscosity decreased at a given temperature as the proportion of carbohydrate increased. This may be due to the high water content of vegetable & fruits as the total solids fraction is likely to be a key controlling factor of the rheology. The Herschel-Bulkley model was used successfully to model food waste flow behaviour. Also, a higher strain was needed to break down the structure of the food waste as digestion time increased.

Enhancement of physicochemical, microbiological and sensory properties of dry-cured loin by using processed sulfur-fed pigs

The present study showed that processed sulfur supplementation and processing condition affected changes in physicochemical, microbial and sensory properties of dry-cured loin. The pigs were divided into two groups at the fattening phase: non-sulfur-fed pigs (NSFP) and 0.3% processed sulfur-fed pigs (SFP) in fattening phase. The crude fat content of SFP was lower than that of NSFP in raw meat and dry-cured loin. Lipid and pigment oxidation were suppressed in SFP compared with NSFP during whole process. Lightness of SFP was significantly higher than that of NSFP during storage. SFP showed higher colour stability than did NSFP during storage. Moreover, microbial spoilage of dry-cured loin was greatly prevented in SFP compared with NSFP. Free amino acids related to taste in SFP were significantly higher than those in NSFP. Polyunsaturated fatty acid of dry-cured loin from SFP group was higher than that of NSFP, while saturated fatty acid of NSFP was significantly higher than that of SFP. SFP had higher preference and flavour scores than did NSFP in a sensory test. Feeding processed sulfur improved the meat-quality characteristics and extended the shelf-life of meat products.

Chemical properties of ω-3 fortified gels made of protein isolate recovered with isoelectric solubilisation/precipitation from whole fish

Protein isolate was recovered from whole gutted fish using isoelectric solubilisation/precipitation (ISP). The objective was to determine chemical properties of heat-set gels made of the ISP protein isolate fortified with ω-3 polyunsaturated fatty acids (PUFAs)-rich oils (flaxseed, fish, algae, krill, and blend). The extent of the PUFAs increase, ω-6/ω-3 FAs and unsaturated/saturated FAs ratios, and the indices of thrombogenicity and atherogenicity depended on specific ω-3 PUFAs-rich oil used to fortify protein isolate gels. Lipid oxidation in ω-3 PUFAs fortified gels was minimal, although greater (P<0.05) than control gels (without ω-3 PUFAs fortification). However, all gels were in the slightly rancid, but acceptable range. The commonly used thiobarbituric-acid-reactive-substances (TBARS) assay to determine lipid oxidation in seafood may be inaccurate for samples containing krill oil due to its red pigment, astaxanthin. Protein degradation (total-volatile-basic-nitrogen) was greater (P<0.05) in ω-3 PUFAs fortified gels than control gels. However, all gels were considerably below the acceptability threshold for protein degradation. The shear stress of ω-3 PUFAs fortified gels was generally greater than the control gels and the shear strain was generally unchanged. This study demonstrates that ω-3 PUFAs fortification of protein isolates recovered with ISP from fish processing by-products or whole fish has potential application in the development of functional foods.

A three-prong strategy to develop functional food using protein isolates recovered from chicken processing by-products with isoelectric solubilization/precipitation

BACKGROUND

Skin-on bone-in chicken drumsticks were processed with isoelectric solubilization/precipitation to recover muscle proteins. The drumsticks were used as a model for dark chicken meat processing by-products. The main objective of this study was conversion of dark chicken meat processing by-products to restructured functional food product. An attempt was made to develop functional food product that would resemble respective product made from boneless skinless chicken breast meat. A three-prong strategy to address diet-driven cardiovascular disease (CVD)with a functional food was used in this study. The strategy included addition of three ingredients with well-documented cardiovascular benefits: (i) ω-3 polyunsaturated fatty acid-rich oil (flaxseed-algae, 9:1); (ii) soluble fiber; and (iii) salt substitute. Titanium dioxide, potato starch, polyphosphate, and transglutaminase were also added. The batters were formulated and cooked resulting in heat-set gels.

RESULTS

Color (L*a*b*), texture (torsion test, Kramer shear test, and texture profile analysis), thermal denaturation (differential scanning calorimetry), and gelation (dynamic rheology) of chicken drumstick gels and chicken breast gels were determined and compared. Chicken drumstick gels generally had comparable color and texture properties to the gels made from chicken breast meat. The endothermic transition (thermal denaturation) of myosin was more pronounced and gelation properties were better for the drumstick gels.

CONCLUSION

This study demonstrated a feasibility to develop functional food made of muscle proteins recovered with isoelectric solubilization/precipitation from low-value dark chicken meat processing by-products. The functional food developed in this study was enriched with CVD-beneficial nutrients and had comparable instrumental quality attributes to respective products made of chicken breast meat. Although the results of this study point towards the potential for a novel, marketable functional food product, sensory tests and storage stability study are recommended.

Isoelectric solubilization/precipitation as a means to recover protein isolate from striped bass (Morone saxatilis) and its physicochemical properties in a nutraceutical seafood product

Excessive dietary intake of Na (i.e., NaCl) contributes to hypertension, which is a major risk factor for cardiovascular disease. Normally, NaOH and HCl are used to dissolve and precipitate, respectively, fish muscle proteins in isoelectric solubilization/precipitation (ISP), therefore contributing to increased Na content in the recovered fish protein isolates (FPI). Substitution of NaOH with KOH may decrease the Na content in FPI and, thus, allow development of reduced-Na seafood products. In this study, FPI was recovered with ISP using NaOH or KOH. In order to develop a nutraceutical seafood product, the FPI was extracted with NaCl or KCl-based salt substitute and subjected to cold- or heat-gelation. In addition, standard nutraceutical additives (ω-3 fatty acids-rich oil and dietary fiber) along with titanium dioxide (TiO2) were added to FPI. Color, texture, dynamic rheology, Na and K content, and lipid oxidation of the FPI gels were compared to commercial Alaska pollock surimi gels. FPI gels had greater (p < 0.05) whiteness, good color properties (L*a*b*), and generally better textural properties when compared to surimi gels. Although the ISP-recovered FPI and surimi developed similar final gel elasticity, the proteins in FPI and surimi had different gelation pattern. A reduction (p < 0.05) of Na content and simultaneous increase (p < 0.05) in K content of FPI gels was achieved by the substitution of NaOH with KOH during ISP and NaCl with the KCl-based salt substitute during formulation of the FPI paste. Although cooking and addition of NaCl during formulation of the FPI paste increased (p < 0.05) lipid oxidation in FPI gels, TBARS values were much below rancidity levels. These results indicate that KOH can replace NaOH to recover FPI from whole gutted fish for subsequent development of nutraceutical seafood products tailored for reduction of diet-driven cardiovascular disease.