Heat-induced pressed gels from canola press cakes: Exploring the impact of starting materials, stirring conditions, and carbohydrase pretreatment

Alternative plant protein sources offer excellent solutions for tackling the current challenge of food insecurity and sustainability. Inspired by soy tofu, pressed gels represent a robust and versatile way to create protein-enriched plant products. Here, production of heat-induced pressed gels from canola cold-pressed cakes (CPC) and hot-pressed cakes (HPC) was investigated under varied stirring conditions. Pressed gels prepared from CPC resulted in a greater yield and protein recovery than that of HPC. While using carbohydrases as a pretreatment was ineffective in improving yield and protein recovery, applying a stirring condition during heating increased the protein recovery up to 38.3%. Also, stirring condition was proved to be able to modulate the textural properties by controlling the compactness and the size of aggregates. It is revealed that pressed gels are stabilized through a combination of hydrogen bonds, hydrophobic interactions, and disulfide bonds. In comparison to canola press cake, the pressed gels contained less glucosinolates and phenolic compounds, but more phytic acid. A mechanism of formation has been hypothesized based on the nucleation-growth mechanism, and a shift was proposed from diffusion-limited processes in non-stirred pressed gels to reaction-limited process in stirred pressed gels. In conclusion, the potential of canola heat-induced pressed gels was demonstrated both as a stand-alone product and a micro-structured protein extract.

Dietary fibre effects and the interplay with exogenous carbohydrases in poultry nutrition

A comprehensive understanding of the role of dietary fibre in non-ruminant animal production is elusive. Equivocal and conflated definitions of fibre coupled with significant analytical complexity, interact with poorly defined host and microbiome relationships. Dietary fibre is known to influence gut development, feed intake and passage rate, nutrient absorption, microbiome taxonomy and function, gut pH, endogenous nutrient loss, environmental sustainability, animal welfare and more. Whilst significant gaps persist in our understanding of fibre in non-ruminant animal production, there is substantial interest in optimizing the fibre fraction of feed to induce high value phenotypes such as improved welfare, live performance and to reduce the environmental footprint of animal production systems. In order to achieve these aspirational goals, it is important to tackle dietary fibre with the same level of scrutiny as is currently done for other critical nutrient classes such as protein, minerals and vitamins. The chemical, mechanical and nutritional role of fibre must be explored at the level of monomeric sugars, oligosaccharides and polysaccharides of varying molecular weight and decoration, and this must be in parallel to standardisation of analytical tools and definitions for speciation. To further complicate subject, exogenous carbohydrases recognise dietary fibre as a focal substrate and have varying capacity to generate lower molecular weight carbohydrates that interact differentially with the host and the enteric microbiome. This short review article will explore the interactive space between dietary fibre and exogenous carbohydrases and will include their nutritional and health effects with emphasis on functional development of the gut, microbiome modulation and host metabolism.

Influence of pectin domains and protein on the viscosity and gelation properties of alkali-extracted pectin from green tea residue

Alkaline pectin extract (APE) from green tea residues has lower viscosity and gelation properties than commercial citrus pectin. To improve the viscosity and gelation properties of APE, four treatments, namely degradation of homogalacturonan (HG) or rhamnogalacturonan (RG) I domains, esterification, and protein removal and degradation, were applied. With proper degradation of the HG or RG I domains (arabinan or galactan), the viscosity of APE increased from 12 to 2.5×104 or 5.0×103 mPa·s, respectively, and the numbers further increased by approximately 500 times with the addition of Ca2+. Other treatments had slight effects on APE viscosity. The strongest gel (G' = 6.7 × 103 Pa and G″ = 930 Pa) was made using the polygalacturonase treated APE with Ca2+ addition. Degradation of the HG domain or protein enhanced APE's self-crosslink effect, while all methods except protein degradation improved the calcium bridging effect, potentially improving the market potential of pectin from biowaste.

Enhancing meat quality of weaned piglets with the dietary incorporation of Ulva lactuca and carbohydrases supplementation

The impact of the dietary incorporation of 7% Ulva lactuca, a green seaweed, on the quality and nutritional value of piglet's meat was assessed. U. lactuca is rich in nutrients and bioactive compounds but its cell wall is composed of complex polysaccharides that reduce their bioavailability. Therefore, the effect of supplementing piglet diets with exogenous carbohydrases was also assessed here. A total of 40 male weaned piglets were divided into four dietary groups, each with 10 piglets: control (wheat, maize and soybean meal-based diet), UL (7% U. lactuca replacing the control diet), UL + R (UL and 0.005% Rovabio®), and UL + E (UL and 0.01% ulvan lyase). The piglets were fed the diets for 2 weeks. The results showed that incorporating U. lactuca in piglet diets did not influence most of the meat quality traits (P > 0.05). However, the incorporation of U. lactuca with the commercial carbohydrase (UL + R) increased the amount of the docosahexaenoic acid (DHA; 22:6n-3) in their meat (P = 0.011) compared with the control, by 54%. In addition, meat from piglets fed seaweed diets showed a nearly two-fold increase in iodine contents (P < 0.001). Meat tenderness, juiciness and overall acceptability of piglets fed the control diet and the UL diet were lower than those fed the diets containing seaweed and carbohydrases (P < 0.001). Overall, the findings indicate that 7% U. lactuca in the diets of weaned piglets had no major detrimental effects on meat quality and their carbohydrase supplementation has the potential to improve meat sensory traits.

Quantification of hydrolysis activity in a biological wastewater treatment context

This paper reviews currently available methods for hydrolysis activity monitoring of the most commonly encountered enzyme categories in biological wastewater treatment. While highlighting the relevant methods for protein, lipid, carbohydrate, organic phosphate, and ester hydrolysis, the discussion of their pros and cons is predominantly aimed at revealing the relevance of the to-be-hydrolyzed substrates that are used in the methods. These "substrates" should mimic the proteins, lipids, or other polymers that are present in the wastewater and are in the reviewed methods (i) real substrates (i.e., naturally present in the wastewater), (ii) chromogenic substrates, or (iii) fluorogenic substrates. We conclude that exploiting relevant substrates such as casein or starch, containing fluorophores, has the highest potential for meaningful high throughput hydrolysis quantification and that lipase activity monitoring is still cumbersome. Monitoring the hydrolysis activity in biological wastewater treatment systems is an underdeveloped area. With this review, which aims at providing a condensed and practice-oriented overview, we hope to facilitate the start or continuation of such monitoring. This monitoring will only grow in importance, given the transition from wastewater treatment plants towards water resource recovery facilities. KEY POINTS: • Colorimetric-based methods are vulnerable to sludge matrix interference. • Bonds in p-nitrophenol-based methods are not representative for the targeted substrates. • Direct methods with relevant/real substrates are preferred. • Fluorophore-containing (real) substrates enable high throughput screening.

Properties of corn-expressed carbohydrase AC1 in swine diets and its effects on apparent ileal digestibility, performance, hematology, and serum chemistry

Carbohydrases are often incorporated into livestock feed as digestive aids to improve animal performance. AC1 is a thermostable carbohydrase with β-1,4-glucanase, endo-cellulase, and cellobiohydrolase activity. AC1 has been expressed in corn, where it accumulates in the grain for easy inclusion in animal diets. Incorporating the enzyme in high-fiber diets (corn-soy supplemented with distiller's dry grains with solubles) that were fed to 5-week-old pigs led to a trend of decreasing viscosity of the digesta as the dose of the enzyme increased (P = 0.092). AC1 also tended to increase the apparent ileal digestibility (AID) of neutral detergent fiber (P = 0.076). When fed diets containing 2126 U/kg AC1, pigs experienced no adverse effects in terms of performance metrics (body weights, average daily gain, average daily feed intake and gain-to-feed ratio), hematology, blood chemistry or general health when compared to pigs fed a control diet that lacked AC1.

Enzymatic pretreatment in the extraction process of soybean to improve protein and isoflavone recovery and to favor aglycone formation

This research aimed to evaluate the pretreatment of soybean with the carbohydrase multi-enzyme complex "Viscozyme L", during the extraction process; in order to improve the recovery of proteins and isoflavones in soybase, and reduce the loss of these compounds through the okara residue. Three concentrations of enzyme were studied at 50 °C, along with an experiment carried out without enzyme addition (control experiment). The results were also evaluated in relation to standard soybase processing. In comparison to the standard and control processes, the enzymatic pretreatment reduced up to 85% the total amount of okara residue. Due to the action of the multi-enzyme complex, protein and total isoflavone recovery increased from 42% to 83% and from 59% to 93%, respectively. The application of Viscozyme L also favored the conversion of conjugated forms of isoflavone to aglycone in the soybase, representing up to 50% of the total isoflavones. The enzymatic pretreatment of soybean with carbohydrase improved the nutritional quality of the soybase, while at the same time reducing residue generation; showing that the proposed food process can be considered environmentally friendly method.

Effects of different carbohydrases on the physicochemical properties of rice flour, and the quality characteristics of fermented rice cake

The rice flours were hydrolyzed using α-amylase (A), α-amylase and xylanase (AX), and α-amylase, xylanase and β-amylase (AXB). The effects of different enzymatic rice flour hydrolysates (ERH) on the quality of the fermented rice cake (FRC) were determined at 25 °C for 4 days. ERH had higher porosity, water absorption index, water solubility index and lower viscosity than the control. Moisture content of FRC center decreased significantly after 4 days. Specific volumes of fresh A-, AX- and AXB-FRC were higher than the control. Color of fresh A-FRC was closer to that of the control. AXB-FRC had lower hardness and firming rate than other samples during storage. After 4 days of storage, FRC with ERH had lower endotherm enthalpy and more uniform and clearer pore structure than the control. Therefore, the ERH with single or mixed enzymes could improve the structure of FRC, and extend its shelf-life.

Effects of dietary carbohydrases on productive performance and immune responses of lactating sows and their piglets

This study was conducted to evaluate effects of dietary multi-carbohydrases (MCS) in a lactating sow diet on productive performance and immune responses of sows and their piglets. A total of 12 sows (218.37 ± 5.5 kg BW; 2 parity) were randomly assigned to 2 dietary treatments: a diet based on corn-soybean meal (CON) and CON with 0.01% MCS. The MCS contained xylanase (2,700 units/g), β-glucanase (700 units/g), and cellulase (800 units/g). Sows were fed the dietary treatments for 28 days (weaning) after farrowing. Blood samples were collected from sows on d 0, 3, and 7 after farrowing and randomly selected 2 nursing piglets in each sow on d 3, 7, and 14 after birth. Measurements were productive performance of sows, frequency of diarrhea of piglets, and immune responses of sows and their piglets. Sows fed MCS had lower (p < 0.05) their body weight change than those fed CON. Piglets from sows fed MCS had higher (p < 0.05) average weight gain and body weight at weaning day and lower (p < 0.10) frequency of diarrhea than those from sows fed CON. Sows fed MCS had lower number of white blood cells (WBC) on d 3 (p < 0.05) and TGF-β1 on d 7 (p < 0.10) during lactation than those fed CON. Similarly, piglets from sows fed MCS had also lower (p < 0.05) number of WBC on d 3 and d 7 and TGF-β1 and C-reactive protein on d 7 during lactation than those from sows fed CON. In addition, piglets from sows fed MCS had higher (p < 0.10) immunoglobulin G and M on d 7 during lactation those from sows fed CON. In conclusion, addition of dietary MCS in the lactating sow diet based on corn and soybean meal improved productive performance of sows and their litters and modulated their immune responses.

Influence of dietary carbohydrases, individually or in combination with phytase or an acidifier, on performance, gut morphology and microbial population in broiler chickens fed a wheat-based diet

The objective of this study was to examine the effects of dietary carbohydrases (xylanase and β-glucanase; XG), individually or in combination with phytase or acidifier on the growth performance, carcass attributes, intestinal microbial counts and morphology in broiler chickens fed a wheat-based diet. A total of 240 one-day-old male broiler chicks were randomly allocated into 4 treatment groups with 6 replicates of 10 birds each. The dietary treatments included a basal diet, the basal diet with an enzyme complex containing XG, XG plus a microbial phytase (XG + P) and XG plus acidifier (XG + A). The results indicated that feed conversion ratio (FCR) was improved in broiler chickens which received XG + A during the entire production period (1 to 35 d) of the trial (P < 0.05). The broiler chickens fed XG + P had lower feed intake compared with the control group at 29 to 35 d of age. The experimental treatments had no effect on the body weight gain of broiler chickens. In carcass traits, except for spleen (P < 0.05), the dietary treatments had no effects on the carcass characteristics of broiler chickens. The birds which received diets supplemented with XG and XG + A had a lower weight of the spleen compare with the control. Addition of XG in combination with phytase (XG + P) resulted in a decrease in ileal enumeration of Escherichia coli at 35 d of age (P < 0.05). However, dietary treatments did not alter the population of ileal Lactobacilli in broiler chickens. Supplementing carbohydrases with phytase and acidifier (XG + P and XG + A) significantly increased the intestinal villus length at 35 d of age (P < 0.05). In conclusion, the present study demonstrated that supplementation of the wheat-based diet with a combination with carbohydrases and acidifier (XG + A) improves FCR in broiler chickens. Furthermore, combinations of carbohydrases with phytase (XG + P) and with acidifier (XG + A) decrease the E. coli counts and increase the villus length in broiler chickens.

Total phenolic content and biological activities of enzymatic extracts from Sargassum muticum (Yendo) Fensholt

Seaweeds are potentially excellent sources of bioactive metabolites that could represent useful leads in the development of new functional ingredients in pharmaceutical and cosmetic industries. In the last decade, new marine bioprocess technologies have allowed the isolation of substances with biological properties. The brown alga Sargassum muticum (Yendo) Fensholt (Ochrophyta) was enzymatically hydrolyzed to prepare water-soluble extracts by using six different commercially available carbohydrate-degrading enzymes and two proteases. Evaluation of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) antioxidant, tyrosinase, elastase, and biofilm inhibition, antibacterial and antiviral activities as well as evaluation of cytotoxicity were realized for each extract. Total phenolic content was measured for extract characterization, and solid-phase extraction was useful to purify the enzymatic extract. Soluble total phenolic content of S. muticum Viscozyme extract was highest with 6.4% of dry weight. Enzymatic Celluclast and Viscozyme extracts had the lowest value of DPPH IC₅₀ indicating a strong antiradical activity, 0.6 mg mL^-1, in comparison with other enzymes. The ferric reducing antioxidant power ranged between 48.7 μM Fe²⁺ Eq, digested with Viscozyme, and 60.8 μM Fe²⁺ Eq, digested with Amyloglucosidase. Tyrosinase inhibition activity of S. muticum Neutrase extract was 41.3% higher compared to other enzymes. Elastase inhibition activity of S. muticum Shearzyme extract had highest activity (32.8%). All enzymatic extracts showed no cytotoxic effect towards the kidney Vero cells. Meanwhile, only S. muticum Neutrase and Alcalase extracts exhibited potential antiviral activity. In addition, S. muticum Viscozyme and Shearzyme extracts showed promising activity in suppressing the biofilm formation against Pseudomonas aeruginosa and Escherichia coli, respectively. Purification of S. muticum Viscozyme extracts by solid-phase extraction managed to concentrate the phenolic content and improve the bioactivity. These results indicate the promising potential of enzyme-assisted followed by solid-phase extraction in recovering phenolic content and in improving its bioactivity.

Addition of exogenous enzymes to diets containing grape pomace: Effects on intestinal utilization of catechins and antioxidant status of chickens

Grape pomace (GP) is a rich source of polyphenols with antioxidant capacity. An experiment was conducted to study the effect of GP phenolic compounds included at 5 and 10%, and the addition (individually or combined) of hydrolyzing enzymes (carbohydrase enzyme complex and tannase at 500ppm) on intestinal utilization of catechins and antioxidant status in broiler chickens. A diet supplemented with 200ppm of α-tocopheryl acetate was also used. Our findings demonstrate the capacity of chickens to digest the monomeric (catechin, epicatechin, gallic acid, and epicatechin-O-gallate) and dimeric (procyanidin B1 and procyanidin B2) catechins present in grape pomace. The addition of enzymes (mainly tannase) hydrolyzed the polymeric structures into smaller catechins, but also promoted a lower digestibility of the monomeric and dimeric catechins suggesting that polymeric structures might favour the intestinal utilization of these catechins. The intestinal accumulation of phenolic compounds generated with tannase and with 10% GP reversed the antimicrobial effect against Clostridium perfringens observed with 5% of GP. Grape pomace improved the antioxidant status of the bird, increasing the α-tocopherol and reducing the iron content on plasma, not affecting the plasma gluthatione. Enzymes modified the intestinal utilization of catechins but not additional protective effect was detected on any of the parameters analyzed to evaluate the antioxidant status.

Enzymatic pretreatment of Chlorella vulgaris for biogas production: Influence of urban wastewater as a sole nutrient source on macromolecular profile and biocatalyst efficiency

Two biocatalysts, namely carbohydrases and proteases, were assessed for organic matter solubilisation and methane yield enhancement of microalgae biomass. This study evidenced Chlorella vulgaris carbohydrate accumulation (40% on VSS basis) when grown in urban wastewater. Despite of the carbohydrate prevailing fraction, protease pretreatment showed higher organic matter hydrolysis efficiency (54%). Microscopic observation revealed that carbohydrases affected slightly the cell wall while protease was not selective to wall constituents. Raw and pretreated biomass was digested at 1.5 kg tCOD m(-3) day(-1) organic loading rate (OLR1) and 20 days hydraulic retention time (HRT). The highest methane yield (137 mL CH4 g COD in(-1)) was achieved in the reactor fed with protease pretreated C. vulgaris. Additionally, anaerobic digestion was conducted at OLR2 (3 kg tCOD m(-3) day(-1)) and HRT (15 days). When compared to raw biomass, methane yield increased 5- and 6.3-fold at OLR1 and OLR2, respectively. No inhibitors were detected during the anaerobic digestion.