Association study of crude seed protein and fat concentration in a USDA pea diversity panel.

Pea (Pisum sativum L.) is a key rotational crop and is increasingly important in the food processing sector for its protein. This study focused on identifying diverse high seed protein concentration (SPC) lines in pea plant genetic resources. Objectives included identifying high-protein pea lines, exploring genetic architecture across environments, pinpointing genes and metabolic pathways associated with high protein, and documenting information for single nucleotide polymorphism (SNP)-based marker-assisted selection. From 2019 to 2021, a 487-accession pea diversity panel, More protein, More pea, More profit, was evaluated in a randomized complete block design. DNA was extracted for genomic analysis via genotype-by-sequencing. Phenotypic analysis included protein and fat measurements in seeds and flower color. Genome-wide association study (GWAS) used multiple models, and the Pathways Association Study Tool was used for metabolic pathway analysis. Significant associations were found between SNPs and pea seed protein and fat concentration. Gene Psat7g216440 on chromosome 7, which targets proteins to cellular destinations, including seed storage proteins, was identified as associated with SPC. Genes Psat4g009200, Psat1g199800, Psat1g199960, and Psat1g033960, all involved in lipid metabolism, were associated with fat concentration. GWAS also identified genes annotated for storage proteins associated with fat concentration, indicating a complex relationship between fat and protein. Metabolic pathway analysis identified 20 pathways related to fat and seven to protein concentration, involving fatty acids, amino acid and protein metabolism, and the tricarboxylic acid cycle. These findings will assist in breeding of high-protein, diverse pea cultivars, and SNPs that can be converted to breeder-friendly molecular marker assays are identified for genes associated with high protein.

Impact of functional dietary fiber incorporation on the appearance and mechanical properties of extruded high moisture meat analogs.

The effect of including functional dietary fiber ingredients (FDFI) on the texture and structure of high moisture meat analog (HMMA) was examined in this study. The inclusion of FDFI in this application is hypothesized to act as a label-friendly texture modifier in HMMA while also boosting the product's dietary fiber content. Two inclusion rates (5% and 10% wt/wt) of four functionally unique FDFI ingredients (pea hull, citrus fiber, hydrocolloid oat bran, and powdered cellulose) were blended with wheat protein isolate. Each unique formulation was processed using a high-moisture twin-screw extrusion process at two different screw speeds (200 and 400 rpm). The type of FDFI added affected the mechanical texture attributes (hardness, springiness, cohesiveness, and integrity index) and in-process behavior (torque and pressure) of the resulting HMMA far more than the inclusion rate or screw speed (p > 0.05). The type of FDFI ingredient employed also had the largest qualitative effect on the visual appearance of the resulting HMMA. These observed quality changes correlated well with the physicochemical and structure-function properties of the FDFI ingredients, especially with water-holding and absorption capacities. The incorporation of FDFI is a viable means of modulating HMMA texture and improving the holistic nutrition of these products. PRACTICAL APPLICATION: Adding highly functional, dietary fiber-rich ingredients to processed foods is a viable strategy for improving the nutritional and textural quality of these foods. The results of this study imply that these fibers can be added to meat analogs at nutritionally relevant rates, and the texture of the resulting product can be tailored based on the functional properties of the ingredients deployed.

Cysteine, sodium metabisulfite, and glutathione enhance crosslinking between proteins during high moisture meat analog extrusion processing and may improve the fibrousness of the products.

BACKGROUND: High moisture meat analog (HMMA) products processed using extrusion have become increasingly popular in the last few years. Because the formation of disulfide bonds is believed to play a critical role in the texturization mechanism, this study aimed to understand how chemical compounds capable of reducing disulfide bonds, specifically cysteine, sodium metabisulfite, and glutathione, affect the texture and the chemical interactions between the proteins. METHOD: Wheat protein blended with cysteine, sodium metabisulfite, or glutathione at levels of 0, 0.5, 1.0, 2.5, 5.0, and 7.5 g kg-1 was extruded at three different temperatures (115, 140, and 165 °C) using a co-rotating twin-screw extruder. The feed rate (85 g min-1), the moisture content (600 g kg-1), and the screw speed (300 rpm) were kept constant. Unextruded and extruded material was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, polymeric protein fractionation, and sulfhydryl group/disulfide bond analysis. Extruded samples were further analyzed for their hardness and their anisotropic index. RESULTS: The inclusion of reductants significantly affected the structure of the obtained extrudates. Although reducing agents had a relatively small impact on the total amount of disulfide bonds, their action significantly enhanced crosslinking between the proteins. At select conditions, samples with high fibrousness were specifically obtained when cysteine or sodium metabisulfite was included at levels of 5.0 g kg-1. DISCUSSION: In the presence of reducing agents, it is believed that disulfide bonds are split earlier during the process without binding to them, giving the protein strands more time to unravel and align, leading to a better flow behavior and more fibrous products. © 2024 Society of Chemical Industry.

Talc and calcium carbonate inclusions in direct expanded pea starch extrudates exhibit different behavior under increasing screw speeds.

The ability to modulate direct expanded product structures improves the versatility and range of product applications. The effect of nucleating agents, namely, talc and calcium carbonate (CC), on the expansion characteristics of pea starch extrudates as impacted by screw speed was explored. Pea starch blends with increasing levels of nucleating agents (0.25%, 1%, and 2%) at 18% moisture (w.b.) were extruded across a range of screw speeds (150, 250, 350, and 450 rpm). The water absorption index, water solubility index (WSI), expansion ratio (ER), unit density, and cell count were determined to evaluate the performance of nucleating agents. The nucleating efficiency of CC, as assessed by cell count, improved with increasing screw speeds. In contrast, the nucleating efficiency of talc was influenced by inclusion levels irrespective of screw speed. ER values ranged from 2.10 to 2.88, where higher nucleating agent inclusions and screw speeds corresponded with lower ER values. Increased nucleating agents and screw speeds corresponded to higher WSI values suggesting the nucleating agents promoted starch degradation. The nucleating agents appeared to promote flow instabilities indicated upon assessment of the extrudate surface. PRACTICAL APPLICATION: This study provides helpful information on the expanded extrudate structure of pea starch as influenced by screw speed and nucleating agents. These findings may help the food industry select processing parameters and appropriate nucleating agent inclusion levels when producing new expanded products with unique textures.

Hyperspectral imaging of foodborne pathogens at colony and cellular levels for rapid identification in dairy products.

This study evaluated the efficacy of hyperspectral imaging (HSI) for the rapid identification of pathogens in dairy products at the colony and cellular levels. The colony and cellular levels studies were designed as completely randomized with six replications. Three strains of Listeria monocytogenes, four strains of Escherichia coli O157: H7, Big Six Shiga toxin-producing E. coli, three strains of Staphylococcus aureus, and ten serovars of Salmonella were used in this study. Pure cultures were streaked for isolation on respective selective media, and hyperspectral data (400-1100 nm wavelength) at the colony and cellular levels were collected and stored as reference libraries. Whole milk and whole milk powder were artificially inoculated (<10 CFU/g or mL) with individual pathogenic strains/serovars. All milk and milk powder samples were enriched using brain heart infusion (BHI) broth at 37°C for 24 h, streaked for isolation on the respective selective media, and hyperspectral data for individual pathogenic strains/serovars at the colony and cellular levels were acquired and treated as test samples data. The acquired colony or cellular images were imported into ENVI software and three regions of interest were selected for each image to obtain hyperspectral data for reference libraries and test samples. Using the kNN classifier and cross-validation technique, overall classification accuracies of 90.38% and 34% were obtained for the colony- and cellular-level identification, respectively. The individual classification accuracies of pathogens in dairy products at the colony level varied between 77.5% to 100%, whereas the accuracy varied between 2.78% and 49.17% for the cellular level.

The interaction between wheat and pea protein influences the final chemical and sensory characteristics of extruded high moisture meat analogs.

Plant-based meat analog products, including those produced by extrusion processing, have become increasingly popular. Complete comprehension of the texturization mechanism and the formation of fibrousness would help improve existing products and extend the variety of plant sources used. Therefore, this study aimed to provide improved insight into the mechanism of texturization during the processing of high-moisture meat analog (HMMA) products. Blends with different wheat and pea protein ratios (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100 wheat:pea) were extruded at a screw speed of 400 rpm, two different moisture contents (50% and 55%), and a feed rate of 90 g/min using a co-rotating twin-screw extruder. Extrudates were analyzed for their texture, free sulfhydryl groups, disulfide bonds, and solubility in different extractants relative to the raw ingredient blends. In addition, a sensory analysis was conducted using the rapid and cost-effective "rate-all-that-apply" (RATA) methodology. The interplay between the two protein types had synergistic effects on the system parameters torque, pressure, and specific mechanical energy, as well as on some textural and sensory parameters. Molecular analyses were not influenced by the interplay between wheat and pea protein as the molecular analyses followed linear trends with the pea inclusion level. Analysis of protein solubility suggests that the texturization mechanism differs slightly depending on the protein type. It is suggested that the texturization of wheat protein depends highly on disulfide bonds, whereas the texturization of pea protein relies on the combination of disulfide bonds and non-covalent interactions. Additionally, RATA was found to be a valuable tool for HMMA products.

Influence of legume-derived proteins with varying solubility on the direct expansion of corn starch during twin-screw extrusion processing.

This study analyzed the effect of the inclusion of legume-derived proteins, specifically pea and fava bean protein, with varying solubility levels on the expansion of corn starch. Three different proteins exhibiting low, medium, or high solubility were mixed with corn starch to obtain blends containing 15%, 25%, and 35% (w/w) of the protein. Extrusion was performed on a twin-screw extruder at three different screw speeds (200, 400, and 600 rpm), a moisture content of 16% (w.b.), and a die temperature of 140°C. Obtained extrudates were analyzed for their expansion, unit density, and hydration properties, namely, water solubility index (WSI) and water absorption index (WAI). Extrudates containing the protein with the highest solubility showed different patterns than those that had proteins with low or medium solubility. Expansion ratio (ER) increased from a maximum of 3.55 ± 0.24 for pure corn starch up to 5.45 ± 0.43 when incorporating 35% of the protein with medium solubility but significantly decreased down to 1.24 ± 0.08 when incorporating 35% of the most soluble protein. The influence on the system parameters, as well as on the hydration properties, was also greatest for the blends containing the protein with the highest solubility. Even though significant Pearson correlations were observed between protein solubility and ER (r = -0.579), unity density (r = 0.614), WSI (r = -0.634), torque (r = -0.612), as well as specific mechanical energy (r = -0.451), further research is needed to evaluate if the solubility is indeed the reason for certain behaviors or if other protein characteristics are more critical for expansion. PRACTICAL APPLICATION: This manuscript provides practical information on the influence of the addition of legume-derived proteins with different solubility levels on direct expansion. The obtained results may help the industry with the selection of the appropriate proteins for inclusion levels in producing high protein direct-expanded extruded food products.

High methoxyl pectin can improve the extrusion characteristics and increase the dietary fiber content of starch-cellulose extrudates.

Improving total dietary fiber content while maintaining the texture/expansion of extruded products is a challenge. Pectin has a dual function; it is a source of dietary fiber and it also functions as a hydrocolloid, which could improve the texture of high-fiber extruded foods. The objective of this study was to evaluate the impacts of pectin types from citrus peel on the expansion characteristics of starch-cellulose extrudates. High and low methoxyl pectin (HMP and LMP) was added to the starch-cellulose mixtures and extruded using a twin-screw extruder. The pasting properties of raw mixtures, extrusion properties, microstructure, and dietary fiber contents of the extrudates were studied. The inclusion of HMP in raw material improved the peak viscosity (629.7 ± 8.1 to 754.7 ± 80.1 mPa s) and maintained the final viscosity compared to the control (starch-cellulose mixture alone), unlike LMP. HMP relatively maintained the extrusion process parameters such as torque, back pressure, and specific mechanical energy as the control. Interestingly, the addition of 7% of HMP had a similar expansion ratio (3.41 ± 0.08 to 2.35 ± 0.06) compared to the control (3.46 ± 0.08 to 2.32 ± 0.09) under the extrusion conditions studied. The total dietary fiber content improved from 12.22 ± 0.01% to 18.26 ± 0.63% (w/w). HMP maintained the expansion characteristic of starch-cellulose extrudates and improved its total dietary fiber content relative to LMP. Adding HMP to the mixtures improved the extensibility of the melt, favoring bubble growth and expansion of the starch-cellulose extrudates. Fourier transform infrared spectroscopy data suggested that there could be intermolecular interactions between starch, cellulose, and pectin, but the nature of these interactions needs further investigation. PRACTICAL APPLICATION: The study provides practical information on the influence of the addition of high and low methoxyl pectin on starch-cellulose extrudates. The results can help the industry to produce snack products that are more nutritious but are still well accepted by the consumers.

Impact of tamarind seed gum on the viscosity behavior, thermal properties, and extrusion characteristics of native corn starch.

Tamarind seed gum (TSG) is a cold-swelling hydrocolloid with remarkable processing stability and starch synergy. Its use in direct expanded extruded foods has not been documented. The thermal and pasting viscosity properties of six TSG (0%, 0.5%, 1.0%, 2.5%, 5.0%, and 7.5% TSG) and native corn starch blends were characterized by differential scanning calorimetry and ViscoQuick, respectively. These same blends were extruded using a corotating twin-screw extruder at four screw speeds (SSs) (150, 300, 450, and 600 rpm). System back pressure, motor torque, and specific mechanical energy (SME) were measured. Extrudate quality metrics, such as expansion ratio (ER), water absorption index (WAI), and water solubility index (WSI), were also measured. The pasting viscosities indicated that TSG inclusion increases viscosity but also makes the starch-gum paste more susceptible to permanent shear degradation. The thermal analysis indicated that TSG inclusion narrowed the melting endotherms and lowered the energy required for melting (p < 0.05) at higher inclusion levels. Extruder back pressure, motor torque, and SME decreased with increasing TSG levels (p < 0.05) as the TSG effectively lowered the melt viscosity at high usage rates. The ER reached a maximum of 3.73 with a 2.5% TSG level extruded at 150 rpm (p < 0.05). The WAI of extrudates increased with TSG inclusion rate at equivalent SSs, whereas WSI behaved oppositely (p < 0.05). Small inclusions of TSG can improve the expansion properties of starch, whereas larger inclusions result in a lubrication effect that mitigates the shear-induced depolymerization of starch. PRACTICAL APPLICATION: The impact of cold-water soluble hydrocolloids, including tamarind seed gum, on the extrusion process, is poorly understood. From this work, tamarind seed gum effectively modifies the viscoelastic and thermal characteristics of corn starch in a way that enhances the direct expansion characteristics of the starch during extrusion processing. The effect is more beneficial at lower gum inclusion levels as higher levels result in reduced capabilities to translate shear from the extruder into useful transformations of the starch polymers during processing. Small amounts of tamarind seed gum could be used to improve the quality of extruded starch puff snacks.

Influences of modified fiber inclusion with varying particle size on corn starch-based extrudate expansion.

The inclusion of cellulose nanocrystals (CNC) and microcrystalline cellulose (MCC) during extrusion processing of corn starch (CS) is presented in this study. Blends were prepared by incorporating CNC and MCC at different concentrations, 1%, 3%, 5%, and 10% w/w in CS. The crystallinity index (CrI) of CNC and MCC was determined using X-ray diffraction, and the chemical functionality of CNC, MCC, and CS was studied using Fourier transform infrared spectroscopy. The pasting properties of the blends were studied using Micro Visco-Amylo-Graph before extrusion. The blends were preconditioned to 18 ± 0.5% (w.b.) moisture and extruded using a twin-screw extruder at 200 and 250 rpm at 140°C. CS-CNC's expansion ratio (ER) values were 2.95 to 3.35 and 2.72 to 3.22 for MCC. CNC's CrI and particle size were significantly lower than MCC, allowing CNC-based extrudates to have ER values similar to the control even at high CNC concentration (≤10% w/w). This study demonstrated that fiber with particle size <100 µm can be added in direct-expanded product formulations at high concentrations without negatively influencing the extrudate texture while offering increased nutritional value. PRACTICAL APPLICATION: This study gives insight into the potential application of cellulose nanocrystals and microcrystalline cellulose in manufacturing direct-expanded extruded products, providing high fiber content without compromising the product quality. This knowledge could also be translated into manufacturing other food products such as breakfast cereals, pasta, and bread.

Different breeding lines of quinoa significantly influence the quality of baked cookies and cooked grains.

Ten advanced breeding lines of quinoa were evaluated for their physicochemical and functional characteristics. These novel breeding lines were used in two model foods, including cookies and cooked grains, to understand the influence of their characteristics on the product quality. The cookies were baked using whole quinoa flour, and the quality attributes of texture, physical dimensions, and color were measured. The whole quinoa grains were cooked with water at a 1:4 (w/w) grain-to-water ratio, and quality attributes including water uptake (WU-G), bulk density (BD-G), and cooking loss (CL-G) were measured. Significant differences in the quality of both products as an impact of the breeding lines were observed. In baked cookies, the WAQ2 variety produced cookies with the lowest diameter, whereas cookies prepared with WAQ1 were significantly softer than other varieties. In terms of cooked quinoa, WAQ8 exhibited the highest WU-G while WAQ1 showed the highest CL-G. Correlations were observed between flour characteristics and final product quality. Cookie height was negatively correlated with protein content, whereas the water solubility index (WSI) of flours had a positive effect on the cookie hardness. The cooking characteristics of quinoa grains were found to be correlated with the thermal properties of whole quinoa flour. The results of this study will help determine the advanced breeding lines for release as commercial varieties and will also provide food processors with information to find suitable quinoa varieties for different food applications. PRACTICAL APPLICATION: New quinoa breeding lines have been developed to be grown in the climate conditions of Washington State. These varieties were characterized to find correlations with food quality for cookies and cooked grains. The results from this study will help farmers navigate among the quinoa varieties and help commercial food producers use the optimal quinoa variety for their specific food products.

Extrusion characteristics of ten novel quinoa breeding lines.

Ten novel breeding lines of quinoa (Chenopodium quinoa Willd) suitable to be grown in the Pacific Northwest of the United States were developed and utilized for extrusion processing. Understanding how a particular breeding line performs during food processing and which properties determine its performance can promote the use of quinoa as an ingredient in value-added products, such as extruded snacks. In this study, extrusion characteristics of the whole seed flours of the novel quinoa breeding lines were evaluated using a co-rotating twin-screw extruder at two temperatures (110°C and 125°C), three screw speeds (200, 350, and 500 rpm), and a moisture content of 18% (w.b.). The expansion ratio (ER) ranged from 1.15 to 2.33 and was negatively influenced by the fat content in the flours. Breeding line 11WAQ-104.88 (WAQ10) exhibited the greatest potential for use in direct expanded foods as it had the highest ER for all conditions studied. Strong correlations were found between ER and pasting properties of the flours, proving the usefulness of the pasting test for flour quality evaluation before extrusion processing. The results demonstrate the potential of using quinoa for producing direct expanded food products and highlight the importance of selecting specific breeding lines for desired product characteristics. PRACTICAL APPLICATION: This study provides the extrusion processing characteristics of 10 new quinoa breeding lines. Based on the information gained, it will be easier for the food industry, including breeders as well as processors, to select the right quinoa variety based on their requirements, and may further help to enhance the use of quinoa.

Potential interactions between starch and fruit pomace may impact the expansion ratio of direct expanded extrudates.

Due to their dense characteristics, direct-expanded products fortified with insoluble fiber are generally not well accepted. Understanding the interactions between starch and fiber could help to effectively choose and modify ingredients to produce products containing high amounts of fiber. Therefore, this study aims to explain the interplay between two starches (native and waxy corn) and two pomace types (blueberry and cranberry). Blends up to 100% of pomace were extruded using a co-rotating twin-screw extruder. Raw material and milled extrudates were analyzed for their pasting and hydration properties. Fourier-transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy were conducted to observe molecular changes. The expansion ratio (ER) significantly decreased as pomace was added and ranged from 3.85 for pure waxy corn starch to approximately 1 for blends that contained 80% pomace. Distinctions between the blends were observed. Particularly, at 20% of pomace inclusion, native corn starch with cranberry pomace showed a significantly higher ER. Different behaviors were also detected during the physicochemical analyses. A nonlinear trend between pomace level and water solubility as well as absorption was observed for native corn starch blends, suggesting that molecular interactions between the biopolymers occur. FTIR and NMR results give no evidence for new covalent bonds; hence, the most likely interactions occurring are hydrogen bonds. In addition to the dilution effect of pomace addition, the enhancement or weakening of such interactions between starch molecules by pomace compounds may reduce the ER.

Heat resistance comparison of Salmonella and Enterococcus faecium in cornmeal at different moisture levels.

Adequate surrogate identification is critical for validating in-plant thermal process controls for Salmonella inactivation in different food matrices. This study compared the thermal inactivation parameters (D- and z-values) and evaluated the heat resistance of Enterococcus faecium (8459) as a surrogate for a 5-serovar Salmonella cocktail in cornmeal. The cornmeal was spray inoculated with the respective bacteria to achieve ~9 log CFU/g population and set to the desired moisture contents (16, 22, and 28% w.b.). The inoculated cornmeal was then heat-treated at pre-determined temperatures (60, 64, and 68 °C) in sealed aluminum thermal-death-time disks in hot water baths for pre-determined time intervals. Injury-recovery media [brain heart infusion (BHI) agar overlaid with xylose lysine deoxycholate (XLD) agar for Salmonella or BHI agar overlaid m-enterococcus agar for E. faecium] were used for microbial enumeration to account for thermally injured bacterial cells. The D-values of Salmonella in cornmeal at 16, 22, and 28% moisture content were 37.5, 8.4, and 2.4 min at 60 °C, 19.9, 3.5, and 1.1 min at 64 °C, and 10.1, 1.4, and 0.5 min at 68 °C, respectively. The D-values of E. faecium in cornmeal at 16, 22, and 28% moisture content were 140.4, 18.9, and 3.3 min at 60 °C, 78.4, 7.1, and 1.6 min at 64 °C, and 37.3, 2.8, and 0.8 min at 68 °C, respectively. The z-values of E. faecium and Salmonella in cornmeal at 16, 22, and 28% moisture content were 13.9, 9.7, and 12.5 °C, and 14.0, 10.4, and 11.7 °C, respectively. These results indicated similar or higher thermal resistance (D-values) and equivalent thermal sensitivity (z-values) of E. faecium compared to Salmonella at different moisture contents and respective temperatures (P ≤ 0.05). Therefore, E. faecium could be used as a surrogate for Salmonella during thermal process validation of cornmeal processing.

Exploration of physicochemical properties and molecular interactions between cellulose and high-amylose cornstarch during extrusion processing.

Incorporating fiber at high levels (>10%) into direct-expanded products with acceptable texture is challenging. Fundamental explanations for the interaction of starch and fiber and the cause of expansion reduction need further understanding for the effective incorporation of fiber into expanded products. This study aims to explain how cellulose content impacts the physicochemical properties of starch-based extrudates and the long-range and short-range molecular changes of starch. Mixtures of cornstarch (50% amylose) and cellulose were extruded using a co-rotating twin-screw extruder. Thermal and pasting properties of the raw mixtures were evaluated, and the physicochemical properties and microstructure of extrudates were determined. Long-range and short-range molecular changes of starch-cellulose mixtures before and after extrusion were observed by X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. The expansion ratio of extrudates reduced significantly as the cellulose content increased and had a strong negative correlation with crystallinity. Cell structures of starch-cellulose extrudates had a smaller and more uniform pore size but possessing a more ruptured matrix. FTIR spectra suggested that there was no covalent bonding interaction between starch and fiber after extrusion. Extrusion reduced the overall crystallinity compared to the raw mixtures. XRD showed that the crystallinity of the starch-cellulose extrudates increased as the cellulose content increased, and the XRD peaks representing cellulose remained unchanged. Cellulose could interfere with starch chain reassociation through intermolecular hydrogen bonding during the expansion process. Phase separation of starch and cellulose is likely to occur at high cellulose content, which could be another reason for the reduced expansion.

Whole seed lentil flours from different varieties (Brewer, Crimson, and Richlea) demonstrated significant variations in their expansion characteristics during extrusion.

The properties of flours and extrusion characteristics, of three lentil varieties (Brewer, Crimson, and Richlea) were studied. The effects of barrel temperature (110, 125, and 140 °C) and screw speed (150, 200, and 250 rpm) on process responses and extrudate characteristics were evaluated using a corotating twin-screw extruder. The three varieties of lentils had significant differences (p < 0.05) in their starch (48.7% to 50.9%), protein (20.4% to 22.7%), and fat content (1.3% to 1.9%), gelatinization temperature (71.7 to 74.6 °C), peak viscosity (123.3 to 179.7 mPa.s), and melting temperature (113.6 to 119.7 °C). The lentil variety, barrel temperature, and screw speed significantly impacted the process responses and extrudate properties. Whole lentil flours exhibited the highest expansion ratio (3.0 to 3.6) at the lowest temperature (110 °C) and the highest screw speed (250 rpm). Richlea variety had the highest expansion ratio (3.6) and the highest water solubility index (45.4%) as it had the highest starch content and peak viscosity, and the lowest protein content and melting temperature. Meanwhile, Brewer variety exhibited the lowest expansion ratio (1.9 to 3.0) compared to Richlea (2.5 to 3.6) and Crimson (2.4 to 3.0) in most of the extrusion conditions studied. Richlea variety was the most suitable for making direct-expanded extrudates among the varieties studied. The significant differences in the properties of flours from the three varieties of lentils resulted in significant impacts on the properties of their extrudates. Therefore, determining the properties of flours of different varieties is useful to select the appropriate varieties for extrusion processing. PRACTICAL APPLICATION: The information from this study is useful for the food industry to select the appropriate lentil varieties and processing conditions for the development of direct-expanded products. The data prove the importance of understanding the chemical composition, pasting, and thermal properties to select the appropriate varieties for extrusion processing.

Desiccation in oil protects bacteria in thermal processing.

Edible oils have long been considered to have a protective effect on bacteria from thermal inactivation, but the mechanism for this effect remains unclear. Our recent study suggests that the water activity (aw) of oil decreases exponentially with increasing temperature. Therefore, in thermal processing, the aw of the bacteria inside oil may also decrease making the bacteria more resistant to heat. To validate this hypothesis, the equilibrium aw of bacteria (Enterococcus faecium NRRL B2354, or E. faecium) in peanut oil samples, with different initial aw (0.93, 0.75, 0.52 & 0.33) at room temperature, were measured at elevated temperatures up to 80 °C. Meanwhile, the thermal resistances of E. faecium in these samples were also tested at 80 °C. Results indicate that the aw of the bacteria-in-oil systems changed in the same manner as that of pure peanut oil; it decreased exponentially with temperature from 0.93, 0.75, 0.52 & 0.33 (at ~23 °C) to 0.36, 0.30, 0.21 & 0.13 (at 80 °C), respectively. This confirmed that bacterial cells experienced desiccation in oil during the thermal treatments. The thermal death rates of E. faecium in peanut oil samples followed first-order kinetics. The D80 value (time needed to achieve 1-log reduction at 80 °C) increased exponentially with the reduced aw at 80 °C, from 87 min at aw 0.36 to 1539 min at aw 0.13. A graphical comparison (logD80 vs. high-temperature aw) showed a similarity between the thermal resistance of E. faecium in oil and that in dry air, which supports the hypothesis that oil protects bacteria from thermal treatments through desiccation.

Pea starch exhibits good expansion characteristics under relatively lower temperatures during extrusion cooking.

Extrusion processing characteristics of pea starch were studied as impacted by various extrusion cooking processing variables, including, moisture content (15%, 17.5%, and 20% w.b.), temperature (120, 135, and 150 °C), and screw speed (150, 200, and 250 rpm), in a co-rotating twin-screw extruder. Physicochemical properties such as radial expansion ratio (ER), unit density (UD), water absorption index (WAI), and water solubility index (WSI) were measured. ER of the extrudates ranged between 2.52 and 3.63. These values of ER were significantly high, although relatively lower compared to the highest values reported in the literature for corn and rice extrudates. The UD values for all the extrudates ranged from 0.12 to 0.35 g/cm3 , WAI, and WSI values ranged from 10.98 to 12.10 g/g and from 0.12% to 7.73%, respectively. Both screw speed and moisture content had significant impacts on the ER (P < 0.01). The highest ER was observed for the extrusion cooking conditions of the lowest moisture content level (15%), lowest barrel temperature (120 °C), and lowest screw speed (150 rpm). The cross-sectional microstructure of the extrudates showed that the samples with a high ER had thick and elongated pores. The results of this study indicate that pea starch is a viable ingredient for making puffed extruded products. PRACTICAL APPLICATION: The food industry can utilize the information generated from this study in the development of extruded expanded food products with pea starch. The specific information related to process conditions can assist the food industry in determining the ideal conditions for extrusion cooking in the production.

Whole nuña bean (Phaseolus vulgaris L.) flour showed higher direct expansion during extrusion processing at relatively lower temperatures.

Nuña bean, also known as "popping" bean, belongs to the group of common beans (Phaseolus vulgaris, L.). Originated in Andean mountains, nuña beans is an important food crop in several South American countries, including Bolivia, Ecuador, and Peru, where it is consumed primarily as a snack. Nuña beans are highly nutritious and have a distinctive nutty flavor, which makes them potentially desirable ingredients in food applications, such as extruded snacks. Thus, the goal of this study was to evaluate the performance of whole seed nuña bean flour during extrusion cooking. Expansion characteristics of whole nuña bean flour were investigated using a twin-screw extruder. Three levels of moisture contents of 15%, 18%, and 21% (wet basis), three barrel temperatures of 120, 140, and 160 °C, and three screw speeds of 150, 200, and 250 rpm were evaluated, with a die diameter of 3.15 mm. The expansion ratio (ER) ranged from 1.41 to 3.03, within the extrusion conditions studied. The moisture content and screw speed were found to have the most significant impact on the ER. Lower temperature and higher screw speed resulted in higher ER. The maximum ER of 3.03 was observed at a moisture content of 15%, a barrel temperature of 120 °C, and a screw speed of 250 rpm. Nuña bean flour exhibited good expansion properties at relatively low temperatures, which highlights its potential for use in extruded food applications such as nutritious snacks. PRACTICAL APPLICATION: There is increasing consumer demand for more nutritional snacks and cereals. Nuña bean flour exhibited potential for use in such nutritious products. This provides the industry with an alternative source of protein and fiber for inclusion in expanded food products.

Hurdle Effect of Hot Air Impingement Drying and Surfactant-Sanitizer Wash on Removal of Listeria innocua from Fresh Apples.

ABSTRACT: This study investigated the decontamination efficacy of washing treatments for whole fresh apples by using washes containing surfactants, lauric arginate, sodium dodecyl sulfate, and Tween 20, combined with peracetic acid (PAA), followed by hot air impingement drying. Whole fresh apples of selected varieties (Gala and Granny Smith) were inoculated with Listeria innocua (7 log CFU/mL) by using a dipping method, and then dried and subjected to wash treatments with selected washing solutions (H2O, PAA, PAA-lauric arginate, PAA-sodium dodecyl sulfate, and PAA-Tween 20), followed by hot air impingement drying at two different temperature and time conditions, 93°C for 60 s or 121°C for 25 s. The H2O and PAA wash followed by hot air impingement drying led to a maximum 1.5-log reduction of L. innocua on the fruit surface. Adding surfactants increased the effectiveness of washing and drying treatments, resulting in an approximate 2.2-log reduction. Surfactants increased the spreadability and evaporation rate of the washing solutions. Posttreatment changes in apple firmness were assessed during a 21-day storage at 4 and 21°C. The hot air impingement drying had no adverse effect on the firmness of the apples and did not show any further reduction in L. innocua. Washing apples with solutions containing surfactants combined with PAA followed by hot air impingement drying helped to reduce the microbial loads to some extent and may help to reduce drying times significantly.