Bioengineered Enzymes and Precision Fermentation in the Food Industry.

Enzymes have been used in the food processing industry for many years. However, the use of native enzymes is not conducive to high activity, efficiency, range of substrates, and adaptability to harsh food processing conditions. The advent of enzyme engineering approaches such as rational design, directed evolution, and semi-rational design provided much-needed impetus for tailor-made enzymes with improved or novel catalytic properties. Production of designer enzymes became further refined with the emergence of synthetic biology and gene editing techniques and a plethora of other tools such as artificial intelligence, and computational and bioinformatics analyses which have paved the way for what is referred to as precision fermentation for the production of these designer enzymes more efficiently. With all the technologies available, the bottleneck is now in the scale-up production of these enzymes. There is generally a lack of accessibility thereof of large-scale capabilities and know-how. This review is aimed at highlighting these various enzyme-engineering strategies and the associated scale-up challenges, including safety concerns surrounding genetically modified microorganisms and the use of cell-free systems to circumvent this issue. The use of solid-state fermentation (SSF) is also addressed as a potentially low-cost production system, amenable to customization and employing inexpensive feedstocks as substrate.

Fermentation for Designing Innovative Plant-Based Meat and Dairy Alternatives.

Fermentation was traditionally used all over the world, having the preservation of plant and animal foods as a primary role. Owing to the rise of dairy and meat alternatives, fermentation is booming as an effective technology to improve the sensory, nutritional, and functional profiles of the new generation of plant-based products. This article intends to review the market landscape of fermented plant-based products with a focus on dairy and meat alternatives. Fermentation contributes to improving the organoleptic properties and nutritional profile of dairy and meat alternatives. Precision fermentation provides more opportunities for plant-based meat and dairy manufacturers to deliver a meat/dairy-like experience. Seizing the opportunities that the progress of digitalization is offering would boost the production of high-value ingredients such as enzymes, fats, proteins, and vitamins. Innovative technologies such as 3D printing could be an effective post-processing solution following fermentation in order to mimic the structure and texture of conventional products.

Milling and differential sieving to diversify flour functionality: A comparison between pulses and cereals.

In this study, pulse (pea, lentil) and cereal (barley, oats) seeds were firstly milled into whole flours, which were then sieved into coarse and fine flours. The particle sizes of the three generated flour streams followed a descending order of coarse > whole > fine, consistent with the observation under scanning electron microscopy (SEM). Among the four crops, the three flour streams showed the same rank order of fine > whole > coarse in starch and damaged-starch contents but the opposite order in ash and total dietary fiber contents. Thus, those functional properties closely related to starch occurring in flour, such as L* (brightness), starch gelatinization enthalpy change (ΔH), and gel hardness, followed the same order of fine > whole > coarse. By contrast, protein contents of the three flour streams did not vary in pea and lentil but showed a trend of coarse > whole > fine in barley and oats, which could partially explain generally comparable foaming and emulsifying properties of the three streams of pulse flours as well as an order of coarse > whole > fine in oil-binding capacity (OBC) of cereal flours, respectively. The different particle sizes and chemical compositions of the three flour streams only resulted in a descending order of fine > whole > coarse in the pasting viscosities of the pulse flours but did not lead to such a clear trend in the cereal flours, which could be partly attributable to the different microscopic structures of the pulse and cereal seeds and their corresponding flours. This research clearly demonstrated that particle size, chemical composition, and microscopic structure were important variables determining the specific techno-functional properties of pulse and cereal flours.

Nutritional Composition and In Vitro Starch Digestibility of Crackers Supplemented with Faba Bean Whole Flour, Starch Concentrate, Protein Concentrate and Protein Isolate.

The nutritional quality of common wheat-based foods can be improved by adding flours from whole pulses or their carbohydrate and protein constituents. Faba bean (Vicia faba L.) is a pulse with high protein concentration. In this study, prepared faba bean (FB) flours were added to wheat based baked crackers. Wheat cracker recipes were modified by substituting forty percent wheat flour with flours from whole faba bean, starch enriched flour (starch 60%), protein concentrate (protein 60%) or protein isolate (protein 90%). Baked crackers were ground into meal and analyzed for their macronutrient composition, starch characteristics and in vitro starch hydrolysis. Faba bean supplemented crackers had lower (p ≤ 0.001) total starch concentrations, but proportionally higher protein (16.8-43%), dietary fiber (6.7-12.1%), fat (4.8-7.1%) and resistant starch (3.2-6%) (p ≤ 0.001) than wheat crackers (protein: 16.2%, dietary fiber: 6.3%, fat: 4.2, resistant starch: 1.2%). The increased amylose, amylopectin B1- chain and fat concentration from faba bean flour and starch flour supplementation in cracker recipe contributed to increased resistant starch. Flours from whole faba bean, starch or protein fractions improved the nutritional properties and functional value of the wheat-based crackers. The analytical analysis describing protein, starch composition and structure and in vitro enzymatic hydrolysis advance understanding of factors that account for the in vivo benefits of faba bean flours added to crackers in human physiological functions as also previously shown for pasta. The findings can be used to guide development of improve nutritional quality of similar wheat-based food products.

Faba bean meal, starch or protein fortification of durum wheat pasta differentially influence noodle composition, starch structure and in vitro digestibility.

Faba bean (Vicia faba L.) flour, starch concentrate (60% starch), protein concentrate (~60% protein) and protein isolate (~85% protein) were added to replace one-quarter of durum wheat semolina to enrich the nutritional quality and physiological functions of durum wheat (Triticum turgidum L.) pasta. The raw pasta samples prepared with protein concentrate or isolate had higher (p ≤ 0.001) protein and lower (p ≤ 0.001) total starch concentrations, along with increased total dietary fiber and slowly digestible starch (p ≤ 0.001) than durum wheat semolina control or those with added whole faba-bean flour or isolated starch. The faba bean fortified pasta had altered starch with increased proportion of medium B-type glucan chains and long C-type glucan chains, reduced starch digestibility and were associated with glycaemia related effects in the human diet. The faba bean fortified pasta had increased protein and dietary fiber that influenced food intake and satiety. The results suggest differential contributions of food ingredients in human health outcomes.

Prediction of emulsification behaviour of pea and faba bean protein concentrates and isolates from structure-functionality analysis.

The effects of different extraction methods on the structure-functionality and emulsification behaviour of pea and faba bean protein isolates, and concentrates were studied at pH 7 and 2, and a regression model was developed to predict emulsion characteristics based on protein properties. The concentrates produced by air classification had lower protein content but higher solubility in water compared to the isolates produced by isoelectric precipitation. The protein secondary structure did not show a consistent difference; however, much higher intrinsic fluorescence was observed for the soluble compared to the insoluble fractions. Interfacial tension of all faba proteins was lower than pea, while there was no significant difference between the concentrates and isolates. The higher protein content of the isolates was found to improve their water holding capacity. Canola oil (40 wt%)-in-water coarse emulsions, prepared with 2 wt% proteins and 0.25 wt% xanthan gum showed smaller particle size at pH 7 than pH 2, while the zeta potential, viscosity and gel strength were higher at pH 7. Emulsions stabilized with concentrates were better or comparable to the isolates in terms of particle size, zeta potential, and microstructure. The regression model predicted that an increase in solubility, intrinsic fluorescence, water and oil holding capacities are more favourable to decrease emulsion particle size, while an increase in solubility, intrinsic fluorescence would lead to higher emulsion destabilization. A decrease in interfacial tension was more favourable to lower destabilization. Emulsion viscosity was more dependent on water holding capacity compared to any other factor. Such models could be extremely beneficial for the food industry to modulate processing for the development of desired pulse protein ingredients.

Impact of alcohol washing on the flavour profiles, functionality and protein quality of air classified pea protein enriched flour.

In this study the potential of aqueous solvent washing on removing off-flavours in air classified pea protein-enriched flour (PPEF) was investigated. Unpleasant flavour compounds are one of the main deterrents to the application of pulses. PPEF was treated with ethanol or isopropanol at three different concentrations (20%, 50%, and 80%) to remove the volatiles related to unpleasant beany, earthy and astringent flavours. Headspace solid phase microextraction followed by GC-MS was used to identify the flavour compounds in untreated and treated PPEF. Besides the flavour profile, changes to their proximate composition, colour, functionality and protein quality were compared among untreated and treated samples. Higher concentrations of ethanol and isopropanol (50% and 80%) showed greater effectiveness in removing flavour compounds by reducing the total peak area by 82%-94%. Protein content in all treated samples (58.2%-64.3% d.b.) increased compared to untreated PPEF (55.5%) as a result of purification due to the decrease in ash, lipid and carbohydrate content. However, alcohol treatment reduced the protein solubility and oil holding capacity in all samples by 38.3%-75.9%, and 16.7%-30.2%, respectively. Although in vitro protein digestibility was improved with the solvent treatments, the amino acid scores of those samples became lower (i.e., reduced levels of methionine, cysteine or tryptophan) resulting in up to a 27.8% reduction in in vitro protein digestibility correct amino acid scores. Both ethanol and isopropanol at 50% and 80% concentration proved to be effective in removing flavour compounds in PPEF with some modifications on the chemical compositions, protein functionalities and quality.

Faba bean protein flours added to pasta reduce post-ingestion glycaemia, and increase satiety, protein content and quality.

The hypothesis that adding faba bean (FB) flour and its macronutrient concentrated flours to pasta reduces postprandial glycaemia and increases satiety was tested in 54 young adult males. Each consumed a serving of pasta made from durum wheat semolina (DWS) alone, or DWS flour with 25% of flours from whole FB (FBF), starch concentrate (FBS), protein concentrate (FBPC), or protein isolate (FBPI). Post-consumption measurements included postprandial blood glucose, insulin, C-peptide, GLP-1 and PYY, and subjective appetite, over 120 min. Second meal effects of treatments were assessed after participants consumed either an ad libitum or fixed size meal (12 kcal kg-1) at a pizza meal at 120 min. Additions of FB flours from FBPC and FBPI reduced postprandial glycaemia and appetite, increased protein content and quality of the pastas and PYY and C-peptide responses, but had no effect on plasma insulin or GLP-1. In conclusion, DWS pastas with added faba bean protein flour reduce postprandial BG and appetite and have higher nutritional quality. The clinical trial registry number is NCT02658591 .

Acceptability and characterization of extruded pinto, navy and black beans.

BACKGROUND: Consumption of dry beans has been relatively flat over the last decade. Creating new bean products may increase the consumption of beans and allow more consumers to obtain the health benefits of beans. In this study, pinto, navy and black beans were milled and the resulting flours extruded into puffs. Unflavored extruded puffs were evaluated by untrained panelists using a hedonic scale for appearance, flavor, texture and overall acceptability. The compositions of raw flours and extrudates were characterized. RESULTS: Sensory results indicated that all beans met or exceeded the minimum requirement for acceptability. Overall acceptability of navy and pinto beans was not significantly different, while acceptability of black bean puffs was significantly lower. Total protein (198-217 g kg(-1)) in extrudates was significantly different among the three beans. Total starch ranged from 398 to 406 g kg(-1) and was not significantly different. Resistant starch, total extractable lipid and raffinose contents were significantly reduced by extrusion. Extrusion did not affect crude fiber and phytic acid contents. CONCLUSION: The minimal effects on protein and fiber contents, the significant reduction in raffinose content and the acceptability of the unflavored extruded puffs support using various bean flours as ingredients in extruded puffed products.

Physicochemical Properties of Flaxseed Fortified Extruded Bean Snack.

Milled flaxseed was incorporated (0-20%) into a combination of bean-corn flours and extruded in a twin screw extruder using corn curl method. Physicochemical parameters such as water activity, color, expansion ratio, bulk density, lipid content, and peroxide values of extruded snack were analyzed. Scanning electron micrographs were taken. Peroxide values and propanal contents were measured over four months of storage. Rancidity scores of extruded snack were measured using a trained panel. As expected, omega-3 fatty acids and bulk density increased with increasing flaxseed fortification levels. Extrudates with more flaxseed had decreased lightness values and expansion ratios. However, only the 15 and 20% flaxseed containing extrudates had expansion ratios that were significantly (P ≤ 0.05) different from the control. In general, no significant difference (P > 0.05) in water activity values was observed in the flaxseed fortified extrudates, except in the navy-corn based extrudates. Peroxide values increased with increased flaxseed levels and over a storage period. However, propanal values did not change significantly in the 5-10% flaxseed fortified extrudates but increased in extrudates with higher levels of flaxseed. Rancidity scores were correlated with peroxide values and did not increase significantly during storage under nitrogen flushed conditions.