Showing papers in "Lwt - Food Science and Technology in 2022"

Natural colorants from plant pigments and their encapsulation: An emerging window for the food industry

Abstract: Color is considered to be the primary feature perceived by the senses that represent a crucial role for centuries in the acceptability of foods to enhance their actual appearance and quality. Plant pigments, the impeccable natural source of color, display enormous potential to substitute many of the synthetic colorants. Chlorophylls, carotenoids, anthocyanins, and betalains are the extensive classes of natural colors contributing comprehensive color shades to foods. There are good perspectives for the inclusion of plant pigments in the food industry. Their incorporation into food products is very challenging, as they are chemically unstable and exhibit poor bioavailability. Encapsulation is an excellent process to enhance its bioaccessibility, digestibility, and controlled release. During food fortification, efficient encapsulation technologies are needed to prevent the degradation of pigments and reserve their bioavailability in the human gastrointestinal system. The development of cost-effective and viable technologies for the preparation of natural food color and its application in foods is a great challenge and a major need of the day.

Plant-based proteins and their multifaceted industrial applications

Abstract: Proteins serve as an imperative macronutrient in human nutrition and well-being. Their nutritional quality substantially varies with their digestibility, amino acid profile, bioavailability, processing and purity. From a nutritional viewpoint, the ideal integration of proteins from diverse plant sources can supply an adequate amount of essential amino acids to fulfil human health needs. The use of plant-derived proteins has recently gained momentum due to their multifaceted edible and nonedible applications and their biodegradable nature. The use of plant proteins will be essential when animal-derived proteins fail to satisfy the requirements of the global population. Physicochemical properties, structural properties, amino acid composition and functional attributes of plant-based proteins are of great interest to the food and processing industries. This review presents various applications of plant-based proteins as food supplements in human nutrition, edible coating materials for fruits and vegetables, emulsifiers in numerous food products, sources of bioactive peptides in nutra- and pharmaceutical products, hydrogels in drug delivery and nonedible applications as wood adhesives. Distinct biological properties of proteins obtained from plant sources such as peanuts, soybeans, kidney beans, rice, quinoa, sunflowers, cottonseed, camelina, maize and others are also conceptually discussed based on their diverse applications in human health and nutrition.

Viability of probiotics and antioxidant activity of cashew milk-based yogurt fermented with selected strains of probiotic Lactobacillus spp.

Abstract: The present study investigated the effects of three strains of probiotic Lactobacillus spp. such as Lactobacillus rhamnosus (Lr), Lactobacillus casei (Lc), or Lactobacillus plantarum (Lp) in co-cultures with Streptococcus thermophilus (St) and Lactobacillus delbrueckii subsp. Lactis (Ll) on the changes of post-acidification, viability of lactic acid bacteria (LAB), total phenolic and flavonoid contents, and antioxidant activity of cashew milk (W) - based yogurt (Y) during 0, 7, 14, & 21 days of storage. In addition, sensory evaluation of all yogurt samples was run during the first day of storage. The addition of Lr decreased significantly the pH in cashew milk-based yogurt compared to control-yogurt (C-Y; containing only St and Ll) throughout 21 days of storage. Cashew milk-based yogurt showed an increment in LAB counts, total phenolic and flavonoid contents, and antioxidant capacity content which is relatively dependent on the probiotic Lactobacillus spp. strains. WLp-Y showed lower sensory attributes scores. In conclusion, L. rhamnosus, L. casei, and L. plantarum could be used as a starter culture in cashew milk-based yogurt production with a potential source of natural antioxidants.

The physiochemical and preservation properties of anthocyanidin/chitosan nanocomposite-based edible films containing cinnamon-perilla essential oil pickering nanoemulsions

Abstract: In this study, cinnamon-perilla essential oil (C-PEO) Pickering nanoemulsions were prepared using collagen as an emulsifier, and the effects of Pickering nanoemulsion addition on the structure and properties of anthocyanidin/chitosan nanocomposite-based edible films were investigated. The compatibility of the anthocyanidin/chitosan nanocomposite-based edible films and C-PEO Pickering emulsions were further analyzed by fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. As results, Pickering nanoemulsions containing 1% (v/v) C-PEO (C-PEO-2) had the smallest droplet size (11.84 nm). The edible film exhibited better physical properties (i.e., mechanical, water vapor permeability and thermal stability) after adding C-PEO-2. Furthermore, the hydrophobicity and the antioxidant activity of the film were enhanced after incorporating with C-PEO. Finally, the application of the films to chilled (4) fish fillet preservation was also conducted, wrapping with the edible film was effective in controlling quality changes in fish fillets with lower TVB-N and TBAR values during 8 days of chilled storage. Keywords: Cinnamon-perilla essential oil; Pickering nanoemulsions; Anthocyanidin; Chitosan nanoparticles; Fillet preservation.

Food-derived non-phenolic α-amylase and α-glucosidase inhibitors for controlling starch digestion rate and guiding diabetes-friendly recipes

Abstract: Diabetes is considered one of the biggest health crises in 21st century. Controlling carbohydrate digestibility by inhibiting starch digestive enzyme (α-amylase and α-glucosidase) activities is an efficient strategy to control postprandial hyperglycemia. Over the last decade, synthetic inhibitors are most effective pharmaceutical approach for the management of type 2 diabetes mellitus (T2DM). With the increasing global prevalence of diabetes, identification of alternative enzyme inhibitors with potentially less negative side effects becomes imperative. Compounds of natural sources (such as dietary component) are more desirable due to the advantages in safety, diversity, and economy compared with the synthetic inhibitors. Food-derived non-starch polysaccharides, peptides, and lipids compounds have been determined to inhibit α-amylase and α-glucosidase activities. This review presents updated overview on classification, inhibitory effects, mechanism, and potential application of these inhibitors in foods. The abundant inhibitors in a variety of natural sources give more choices for patients with different requirements, and can guide design of the recipes to prophylactic treatment of T2DM.

Effects of modified sweet potato starch edible coating incorporated with cumin essential oil on storage quality of ‘early crisp’

Abstract: In this study, an edible formulation consisting of modified sweet potato starch (MSPS) and cumin essential oil (CEO) was developed. The effectiveness of the coating on the physiochemical and sensory traits of ‘early crisp’ stored at 25 °C for 28 d was evaluated. The results showed that incorporation of 0.2–0.4% (v/v) CEO in modified sweet potato starch edible coatings significantly (p

Essential oils content, composition and antioxidant activity of lemon balm, mint and sweet basil from Serbia

Abstract: Lemon balm, mint, and basil were used to determine whether light modification (plants grown under pearl shade nets with 40 % shaded index or in un-shaded open field) could improve the quantity and quality of essential oils (EOs) and antioxidant activity. The yield of EOs of lemon balm, mint and sweet basil obtained after 120 min of hydrodistillation was 0.18, 2.00, and 1.12 mL/100 g, respectively. At the same time under shading conditions plants obtained more levels of EOs (0.22, 2.23, and 1.32 mL/100 g). The main components of the lemon balm essential oil are geranial (6.84–7.78 %); neral (3.02–3.52 %) and piperitenone oxide (1.67–5.36 %). The main components of mint essential oil are piperitenone oxide (12–14 %) and 1,8 cineole (1.32–2.27 %), while basil essential oil consists of the following components: linalool (9.06–10.2 %); 1,8 cineole (1.26–8.06 %) and α-trans bergamotene (1.21–1.47 %). The essential oil obtained from basil leaves grown under shading has shown the highest antioxidant activity (EC50 value after 20 min of incubation = 0.68 mg/mL). Medicinal plants are a good source of natural antioxidants with potential application in the food and pharmaceutical industries. Medicinal plants can be recommended to grow in shading conditions for achieving optimal quality parameters.

Preparation of camellia oil pickering emulsion stabilized by glycated whey protein isolate and chitooligosaccharide: Effect on interfacial behavior and emulsion stability

Abstract: Camellia oil has a high content of unsaturated fatty acids and active ingredients, but it is unstable during production, storage, and application. Camellia oil Pickering emulsions were prepared by utilizing electrostatic complex of glycosylated whey protein isolate (gWPI) and chitooligosaccharide (COS) as the emulsifier can be used as an effective carrier system. The effects of pH level and biomass concentration on polymer interaction and emulsion stability were systematically studied. The emulsion's interfacial properties and rheological behavior were studied by using an interfacial tensiometer and a rheometer, respectively. The mass ratio of 1:1 (1%) and pH 5.0 were the optimal conditions for protein–COS interactions. Compared with WPI-COS, the content of absorbed protein in the O/W interface of gWPI-COS increased, and the diffusion (kdiff) and rearrangement (kR) rates of proteins in the O/W interface of the gWPI/gWPI-COS significantly improved according to the rheokinetics of protein adsorption at the oil/water interface. Moreover, a higher viscoelasticity in the WPI/gWPI-COS stabilized the emulsion system. Subsequent studies on the stability of the emulsion also showed that the Pickering emulsions stabilized by gWPI–COS had better thermal stability, oxidative stability, resistance to oscillatory shear than gWPI/WPI or WPI-COS emulsion.

Modification of multi-scale structure, physicochemical properties, and digestibility of rice starch via microwave and cold plasma treatments

Abstract: The effects of microwave (MW) treatments for 30 and 90 s or cold plasma (CP) treatments for 2, 6, and 10 min on structural, physicochemical, and digestive properties of rice starch were investigated and compared with the effects of combined MW and CP treatments. Dual modification of starch using combined MW and CP treatments significantly changed starch granules' morphology, and starch showed lower crystallinity, swelling power, and peak viscosity than rice starch with a single modification. However, no significant changes were found in rice starch's crystalline structure and FT-IR spectra pattern after single or combined treatments. Effects of these treatments on the amylopectin branch chain length distribution and molecular weight of rice starch varied considerably depending on treatment type and treatment duration. Moreover, the dually modified rice starch contained more great content of resistant starch. Thus, the synergistic effects between MW and CP had more profound modification than the single treatment. Also, the dual treatment can be used to produce modified starch for industrial applications.

Effects of different thermal treatment temperatures on volatile flavour compounds of water-boiled salted duck after packaging

Abstract: The aim of this study was to assess the effects of different thermal treatment temperatures on volatile compounds, lipid oxidation, and the Maillard reaction in water-boiled salted duck. A total of 38 flavour compounds were detected, mainly including aldehydes, ketones, alcohols, esters, and furans. The contents of aldehydes, ketones, and furans in duck were significantly increased, while the contents of some alcohols and esters were decreased after high-temperature, high-pressure sterilisation (121 °C, 20 min). Low-temperature heat treatment (85 °C, 50 min; 95 °C, 40 min) had relatively little effect on the flavour of water-boiled salted duck. Thermal treatment significantly promoted the oxidative decomposition of unsaturated fatty acids. Monounsaturated fatty acids may play a key role in the formation of aldehydes and ketones. The Maillard browning was low, and the increase therein remained small after thermal treatment. The study showed that low-temperature heat treatment could better control changes in flavour.

Fruit and vegetable by-products' flours as ingredients: A review on production process, health benefits and technological functionalities

Abstract: Fruits and vegetables are responsible for about 22% of food losses and wastes along the supply chain (not including the retail level). However, fruit and vegetable by-products (FVB) may be transformed into fibre-rich flours and bioactive compounds, mainly bound to the fibre, thus bringing value to the food industry due to health benefits and technological functionality. Therefore, these by-products have great potential to be applied in several food industries. The most common strategy is transforming these by-products into ingredients, and there are some processing strategies for transforming these by-products into dried ingredients - flours. Hence, this review aimed to unveil the most straightforward processes already available and discussed in the literature, allowing an easier implementation at an industrial level, thus achieving an actual application and valorisation of these by-products. The food products where these flours have been applied and the effects on the final products' physicochemical characteristics and health attributes are also critically reviewed.

Green extraction of phenolic compounds from foxtail millet bran by ultrasonic-assisted deep eutectic solvent extraction: Optimization, comparison and bioactivities

Abstract: An ultrasonic-assisted extraction (UAE) protocol using deep eutectic solvent (DES) was employed to extract phenolic compounds from foxtail millet bran (FMB). DES composed with betaine and glycerol in a 1:2 M ratio was selected basing on the total phenolic content (TPC) extraction yield, with the optimal extraction technology investigated using response surface methodology (RSM) with Box-Behnken design (BBD). The optimized process obtained was as follows: DESs with water content of 29 mL/100 mL, ultrasonic power at 247 W, extraction temperature of 61 °C, and extraction time of 31 min. The TPC of the extract was 7.80 ± 0.09 mg ferulic acid equivalent (FAE)/g under the optimum extraction conditions, with the result corresponding well with the model prediction. DES-based UAE produced higher total phenolics, total flavonoids, in vitro antioxidant activity and acetylcholinesterase inhibitory activity than the conventional solvent extraction. The phenolic extract from FMB with DES-based UAE was mainly composed of fifteen phenolic compounds, with p-coumaric acid, apigenin-C-dihexoside, and N′, N″-di-p-coumaroylspermidine being the predominant phenolic compounds. Additionally, 1-O-p-coumaroylglycerol was detected for the first time in FMB. The microstructure differences of the FMB samples following extraction were confirmed using scanning electron microscopy (SEM).

Modifying the structure, physicochemical properties, and foaming ability of amaranth protein by dual pH-shifting and ultrasound treatments

Abstract: Native amaranth protein (APN) is a nutritional ingredient with potential applications for the structuration and functionalization of food products. However, its solubility is poor, which limits its use in the food industry. The effect of ultrasonication (US) at 50% amplitude for 10 min (APUS), pH-shifting at pH 2 and 12 (APpH2 and APpH12), and the combination of both (APpH2US and APpH12US) on the structural, physicochemical, and functional properties of APN were investigated. Alkaline pH-shifting combined with US decreased the hydrodynamic diameter of APN from 1167.0 ± 15.6 nm to 438.3 ± 8.4 nm (APpH12US), whereas acidic pH-shifting increased the hydrodynamic diameter up to 2490.0 ± 5.3 nm (APpH2). Fractions of α-helix, β-sheet, β-turn, and random coil structures of APN were affected by pH12-shifting and US, but pH2-shifting did not. Exposed sulfhydryl groups of the APN diminished, while disulfide bonds increased as a result of pH-shifting alone or combined with US. Zeta potential values revealed that the isoelectric point of APN (4.0) was increased for APpH12 (4.2) and APpH12US (4.5) and decreased for APUS (3.5). The highest solubility was achieved by APpH12US. Foaming capacity and stability were significantly increased in all treatments, except APpH2.

Effect of κ-carrageenan on quality improvement of 3D printed Hypophthalmichthys molitrix-sea cucumber compound surimi product

Abstract: In this study, κ-carrageenan was used as an additive to improve the quality of Hypophthalmichthys molitrix-sea cucumbers (HM-SC) compound surimi gel. The effects of κ-carrageenan on rheological properties, gel strength, textural and moisture characteristics, as well as microstructure of the HM-SC surimi gel were investigated, alongside with Fourier transform infrared (FT-IR) spectroscopic characterization and SDS-PAGE analyses of the compound materials. Rheological tests showed that addition of κ-carrageenan increased the storage modulus of the HM-SC compound materials in a dosage-dependent way, which led to superior shape-forming and shape-keeping abilities in 3D printed products. The best gel strength of 1236.04 g mm was obtained in samples with κ-carrageenan addition at 1.5% (w/w). The microstructure of the HM-SC compound surimi gel became more compact and denser, with improved connectivity. These samples also had reduced cooking loss and improved water holding capacity, confirmed by changes in water mobility characterized through Low-field nuclear magnetic resonance (LF-NMR). Moreover, κ-carrageenan addition did not change protein configuration much, neither was it contributed to the aggregation and degradation of proteins. These results showed that the quality of the HM-SC compound material could be improved with the κ-carrageenan addition, which could make it suitable for 3D printing based novel product development.

Structuring emulsion gels with peanut protein isolate and fish oil and analyzing the mechanical and microstructural characteristics of surimi gel

Abstract: Herein, peanut protein isolate (PPI) and fish oil (FO) emulsion gels are fabricated and added to surimi gel, and their effects on the mechanical and microstructural characteristics of surimi gel are investigated. Emulsion gels consisting of PPI, FO, and water were treated using microbial transglutaminase (MTGase) and termed PPI-based emulsion gels (PEG). Next, surimi gel samples were prepared with PEG contents ranging from 4 to 16 wt%. Texture profile and rheological analyses indicated that compared with the control group obtained by the direct addition of FO, surimi gels with 4–8 wt% PEG showed a significant improvement in hardness, adhesiveness, and chewiness, and had a higher degree of crosslinking. Nevertheless, the color attributes of the surimi gels containing PEG were evidently lower than those of the control group owing to the emulsification in the protein–oil–water system. Moreover, at a concentration of 4–8 wt%, PEG uniformly filled the void spaces of the protein matrix and formed a firmer network structure, as revealed using scanning electron microscopy and confocal laser scanning microscopy. This study provides new sustainable perspectives for the application of PEG fabricated from PPI and FO as a fat substitute in food products.

Contribution of microbial community to flavor formation in tilapia sausage during fermentation with Pediococcus pentosaceus

Abstract: Lactic acid bacteria as starter cultures can lead to rapid acidification for gel formation in fermented fish sausages. However, there is lack of study on the volatile flavor characteristics after starter culture addition and how they affect the microbial community on the flavor formation in fish sausages. In this work, the changes of volatile compounds and microbial community in the tilapia sausage during fermentation with Pediococcus pentosaceus were respectively studied by the headspace solid-phase microextraction gas chromatography-mass spectrometry and 16S rRNA gene high-throughput sequencing. A total of 83 volatile compounds were identified, among which 32 compounds were selected as the core volatile flavor compounds. The microbial diversity in the sausage significantly decreased as the fermentation time increased. There were 12 main microbial genera in whole fermentation stages. The anaerobes such as Pediococcus, Lactococcus, Enterobacter, and Citrobacter increased obviously after fermentation, especially for Pediococcus and Lactococcus, whose total abundance reached over 95% at the end of fermentation. The correlation network model showed that Pediococcus and Lactococcus contributed most to the volatile flavor formation, followed by Enterobacter, Citrobacter, and Photobacterium. This research provides an effective method to accelerate the volatile flavor formation and inhibit the spoilage microorganisms in the fermented tilapia sausage.

The effect of fibrin on rheological behavior, gelling properties and microstructure of myofibrillar proteins

Abstract: The aim of this study was to evaluate water-holding capacity, texture, rheological properties, interactions and microstructure of myofibrillar proteins (MP) gel with the addition of fibrin during the heat-induced process. Compared with the control, whiteness, water-holding capacity and hardness of MP gel with the addition of 2% fibrin increased by 9.70%, 79.36%, 323.07%, respectively. Storage modulus and loss modulus values in 2% fibrin addition group were higher than those of the control. The conformation of random coil gradually transformed to β-sheet and β-turn with the increase of fibrin content; nonspecific association and hydrophobic interactions increased from 14.27 g L−1 and 9.00 g L−1 in the control to 28.96 g L−1 and 12.90 g L−1 in the addition of 2% fibrin, respectively, indicating that these interactions played a key role in the improvement of gelling and rheological properties of MP. Scanning electron microscopy revealed that the incorporation of fibrin facilitated the formation of composited gel with a more ordered and homogeneous gel network structure. These results indicated that fibrin enhanced the functionality of MP, which could be beneficial to the development of gel-type meat products.

Entrapment of curcumin in soy protein isolate using the pH-driven method: Nanoencapsulation and formation mechanism

Abstract: The use of curcumin in the food industry is constrained by its poor aqueous dispersibility and instability. Previous studies have shown that stable curcumin nanoparticles can be prepared using a pH-driven method. In this study, the nanoencapsulation of curcumin by soybean protein isolate (SPI) was achieved using the pH-driven method. The effect of final pH on SPI and SPI-curcumin (SPI-Cur) nanocomposites was determined by analyzing the encapsulation efficiency and stability. SPI had a high encapsulation efficiency for curcumin and was stable, especially at pH 7 and 8. The formation mechanisms of SPI and SPI-Cur were further determined by molecular docking and multispectral analyses. The results showed that hydrogen bond acceptors (O−) of curcumin under alkaline media interacted with the donor groups (N–H) of amino acids to form hydrogen bonds. Throughout the process, hydrophobic interactions promoted the formation of the nanocomposites, and curcumin had a strong static fluorescence quenching effect on SPI. Furthermore, CD spectroscopy demonstrated that the pH-driven method altered the secondary structure of the SPI. This study provides evidence for the interaction mechanism between curcumin and SPI at different pH-driven stages and indicates SPI-Cur can be used as a delivery system of hydrophobic nutraceuticals.

Application of the MTT-based colorimetric method for evaluating bacterial growth using different solvent systems

Abstract: Although the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay is widely used to measure the growth of animal cells, several interfering factors and obstacles for analyzing bacterial growth and for solubilizing bacterial-formazan have been reported. In this study, growth of Gram-negative Escherichia coli and Gram-positive Leuconostoc mesenteroides were analyzed using the MTT assay, and different solvents, specifically dimethyl sulfoxide, 1% Triton X-100, 1% Bile bovine, 10% sodium dodecyl sulfate, and sodium hydroxide (NaOH) were evaluated for solubilizing bacterial-formazan. MTT formazan that had been reduced by L. mesenteroides had fully developed color within 15 min in all the solvents tested. The solvent with the highest peak absorbance was 1 N NaOH. MTT formazan did not have a fully developed color response in the 0.001–0.1 N NaOH range, and its color intensity was not further enhanced at concentrations higher than 1 N. For all solvents, the color intensity of dissolved formazan was significantly higher in E. coli than in L. mesenteroides. The MTT assay showed sufficient sensitivity to detect bacterial cells during early growth phase that could not be detected by the plate counting method. These results suggest that NaOH (1 N) is a suitable solvent for analyzing bacterial growth in MTT assays.

Kappa-carrageenan as an effective cryoprotectant on water mobility and functional properties of grass carp myofibrillar protein gel during frozen storage

Abstract: The effect of kappa-carrageenan oligosaccharides was analyzed on the gelling abilities of grass carp myofibrillar proteins (MP) during 60 days frozen storage. Four gel treatments were prepared: control without additives (C), a positive control with sucrose: sorbitol (PC), and two batches with 1 and 2% of kappa-carrageenan (KC). All MP gels showed a significant decline in the functional and structural properties. Water holding capacity (WHC) and textural properties of control MP gel was significantly reduced due to oxidative changes, whereas weak cross-linking between amino acid molecules and denaturation of myosin observed. In contrast, PC and KC showed a significant control on the reduction of functional properties due to the enhanced inter/intra-molecular interactions and less formation of ice crystals. Addition of KC (2%) significantly restricted the decline in WHC from 95.45 to 75.47%, which is well associated with high hydrogen proton density. Besides that, low field nuclear magnetic resonance (LF-NMR) analysis exhibited a restricted increase in T22 relaxation time in samples added with KC (2%). Overall, MP gel with KC (2%) proved to be an effective alternative in comparison with PC and could be efficient in the production and commercialization of fish and other seafood products.

Treatment with ultrasound improves the encapsulation efficiency of resveratrol in zein-gum Arabic complex coacervates

Abstract: The study was conducted to understand the effect of zein-gum Arabic (GA) complex coacervates prepared by ultrasound treatment on the encapsulation of resveratrol. Compared with zein, zein-GA complex coacervation largely increased the encapsulation efficiency from 26.19% to 55.85% and it was further increased to 74.2% after sonication. Also, prominent rise in the related loading capacities from 2.79% to 6.01% was noted. The increased particle size by the addition of GA and polydispersity index of the ternary complex was dramatically reduced after ultrasound treatment; the absolute values of zeta potential were increased. The hydrogen bonds, electrostatic interactions and hydrophobic effects were the main driving forces for the formation of the ternary complex particles. Ultrasound treatment strengthened the hydrogen bonding and electrostatic interactions, resulting in the formation of compact and homogeneous composite nanoparticles with smaller particle size, which was further confirmed by scanning electron microscope and atomic force microscope. These findings reveal the mechanism of ultrasound enhancing the zein-GA complex coacervation to load resveratrol, and demonstrate its promising effect in modifying protein-polysaccharide complex coacervation as a delivery carrier in the functional food and beverage industry.

Effect of ultrasound-assisted extraction on efficiency, antioxidant activity, and physicochemical properties of sea buckthorn (Hippophae salicipholia) seed oil

Abstract: Effects of ultrasound-assisted extraction (UAE) conditions viz., treatment time, temperature, solvent to sample ratio, and ultrasound power on antioxidant activity, stability, and extraction efficiency of oil from sea buckthorn (Hippophae salicipholia) seed were studied. The treatment time, temperature, and power showed a significant effect (p

Dual cryoprotective and antioxidant effects of silver carp (Hypophthalmichthys molitrix) protein hydrolysates on unwashed surimi stored at conventional and ultra-low frozen temperatures

Abstract: The dual cryoprotective and antioxidant effects of silver carp hydrolysates on unwashed surimi, stored at conventional (−18 °C) or ultra-low (−60 °C) temperatures and subject to three and six freeze-thaw treatments, were examined. The addition of hydrolysates could alleviate the formation of carbonyls of myofibrillar protein, inhibit the decrease of free sulfhydryl content and keep the protein bands stability compared to the control and SuSo group. The lipid peroxidation product malondialdehyde, and the target volatiles hexanal, nonanal and 1-octen-3-ol of the unwashed surimi as detected by HS-SPME-GC-MS, increased slowly under the protection of hydrolysates. The oxidation for proteins and lipids in freeze-thawed samples stored at −18 °C are lower than those of samples stored at −60 °C (p

Structures, physicochemical and bioactive properties of polysaccharides extracted from Panax notoginseng using ultrasonic/microwave-assisted extraction

Abstract: In this study, Panax notoginseng polysaccharides (PNPS) were extracted using ultrasonic/microwave-assisted extraction (UMAE). Based on single-factor experiments, ultrasonic duration, ultrasonic power, microwave duration, and microwave power were optimized using the response surface methodology (RSM). The results indicated that the optimal extraction parameters were an ultrasonic duration of 10 min, ultrasonic power of 50 W, microwave duration of 4 min, and microwave power of 540 W, which resulted in the highest extraction rate of PNPS at 11.03 ± 0.16%. Scanning electron microscopy images indicated that PNPS exhibited a porous and rough structure. The chemical structure of PNPS was analyzed using Fourier transform infrared spectroscopy and ultraviolet–visible spectroscopy. The molecular weight of PNPS was measured to be 4.148 × 105 Da; moreover, PNPS was found to be composed of glucose, galactose, galacturonic acid, arabinose, glucuronic acid, rhamnose, mannose, and ribose. The DPPH scavenging efficiency of PNPS (5 mg/mL) was evaluated to be 65.74%. Upon in vitro simulated saliva–gastrointestinal digestion, partly digested PNPS was obtained. In addition, differential scanning calorimetry (DSC) analysis and rheological testing results indicated that PNPS exhibited high thermal stability and favorable rheological properties. Therefore, PNPS extracted using UMAE exhibited broad application prospects for functional foods and pharmaceuticals.

Structural and rheological properties of meat analogues from Haematococcus pluvialis residue-pea protein by high moisture extrusion

Abstract: Meat analogues, a kind of healthy promising meat substitute, are gaining more and more attention due to its eco-friendly, personal satisfactory and low cost benefits. In this study, Haematococcus pluvialis residue (HPR) was used for preparing pea protein-based meat analogues by high moisture extrusion. Mixed raw material with HPR contents ranging from 10 g/100g to 40 g/100g can successfully be extruded under high moisture of 50 g/100g. The reddish color of HPR made the extrudates look like dried red meat. HPR could markedly improve the textural properties by loosening the layered and the fibrous structures of meat analogues. The fibrous degree of meat analogues with 10 g/100g (dry basis) HPR content reached the maximum (1.28 ± 0.05). Even though the HPR content increased to 40 g/100g (dry basis), the fibrous degree of meat analogues was 1.15 ± 0.03, which was higher than the extrudates without HPR (1.08 ± 0.05). The mechanism of forming meat analogues with better texture was mainly caused by the increased free water content and β-Sheet structure of extrudates after adding HPR. On the whole, HPR can be used as a raw material for high moisture extrusion to enhance the physical properties of meat analogues.

Substitution of rice flour with rice protein improved quality of gluten-free rice spaghetti processed using single screw extrusion

Abstract: Rice protein (RP) has attracted interest as a hypoallergenic protein. In this study, RP was used to improve cooking quality, physicochemical properties, and sensory attributes of gluten-free rice spaghetti (GFRS). GFRS samples were developed by replacing rice flour with rice protein concentrate at 0% (control), 2.5%, 5.0%, 7.5% and 10% (w/w), processed through a single screw extruder. Pasting properties and gel texture of rice flour, protein content, microstructure, cooking quality, texture properties, and sensory attributes of GFRS were determined and compared with GFRS without RP and wheat spaghetti. Substitution of rice flour by 5%–10% RP significantly decreased cooking time and cooking loss. GFRS with 5%–10% RP was more porous than GFRS without RP. Sensory evaluation showed that GFRS containing 2.5% and 5% RP had a high overall linking score which was comparable with wheat spaghetti. Results suggested that RP showed potential to improve the cooking quality and physicochemical properties of GFRS with high acceptability.

Processing sheep milk by cold plasma technology: Impacts on the microbial inactivation, physicochemical characteristics, and protein structure

Abstract: This study aimed to evaluate the impacts of cold plasma processing time of 30 s, 180 s, and 300 s (CSM30, CSM180, and CSM300) on the microbial inactivation, physicochemical characteristics, and protein structure of raw sheep milk. Pasteurized sheep milk was used as the positive control. The microbial inactivation rate of CSM300 sample was similar to the pasteurized sample, and the former had a significantly smaller casein micelle size and polydispersity index (P

Application of lactic acid bacteria for improving the quality of reduced-salt dry fermented sausage: Texture, color, and flavor profiles

Abstract: The traditional dry sausage is highly appreciated in China because of its unique quality characteristics, but it contains high salt content. Hence, this study aimed to evaluate the effects of lactic acid bacteria (LAB) comprising Lactobacillus sakei (LS), Lactobacillus curvatus (LC), Lactobacillus plantarum (LP), and Weissella hellenica (WH) on the quality attributes of the reduced-salt dry fermented sausages. The results indicated that the LP sausage showed higher (P

Identification of odor compounds and odor-active compounds of yogurt using DHS, SPME, SAFE, and SBSE/GC-O-MS

Abstract: Yogurt is widely acknowledged as a healthy dairy product with unique aroma. However, the changes in the odor compounds often affect the storage and shelf life of yogurt. Besides, the complex colloidal system and low concentration levels of most of odorants make it more difficult to be analyzed. Therefore, this study extracted the odor compounds of yogurt through four extraction methods, including dynamic headspace sampling (DHS), solid phase micro-extraction (SPME), solvent-assisted flavor evaporation (SAFE), and Stir bar sorptive extraction (SBSE). A total of 117 odorants, including 27 esters, 27 alcohols, 22 ketones, 16 acids, 15 aldehydes, 5 sulfides, and 5 other compounds, were identified. Of which, 31 odor-active compounds were perceived, and 12 compounds were smelled for the first time in yogurt. Of the four methods, DHS showed the most outstanding extraction effect by obtaining 88 odor compounds. Around 13 volatiles were characterized as the key odor-active compounds of yogurt. Similarly, acetophenone and butyl acrylate were detected as the key odor-active compounds of yogurt for the first time. 2,3-Butanedione was the vital odor-active compound with the highest flavor dilution (FD) factor in yogurt. The results concluded that the odor-active compounds in yogurt might have synergistic and masking effects between them.

Effect of heat-induced aggregation of soy protein isolate on protein-glutaminase deamidation and the emulsifying properties of deamidated products

Abstract: The effects of heat-induced soy protein isolate (SPI) aggregation on enzymatic deamidation by protein-glutaminase (PG) and the emulsifying properties of deamidated products were investigated. The particle size distribution indicated that different aggregates were obtained by preheating SPI at three different temperatures (70 °C, 100 °C, 121 °C) for 10 min. The time-dependent degree of deamidation showed that aggregates formed by preheating treatment had a different influence on the PG deamidation reaction. Preheating treatment at 70 °C could accelerate the PG deamidation reaction and preheating treatment at 121 °C restrained this reaction. The molecular weight distribution revealed that PG deamidation caused the formation of larger aggregates. Electrophoresis analysis and the structural properties indicated that the aggregation caused by PG deamidation was probably a result of hydrophobic interaction and the formation of disulfide bonds. PG deamidation of native or preheated SPI can improve the emulsifying activity, especially in the sample preheated at 70 °C. For SPI samples preheated at 70 °C and 100 °C, the emulsifying stability increased by PG deamidation. In conclusion, preheating can influence the PG deamidation reaction and the emulsifying properties of deamidated products.