•Increasing bean flour increased density and decreased expansion.•Negative effects of bean flour on expansion were attenuated by decreasing moisture.•Resistant starch increased as bean flour and feed ...moisture increased.•In vitro protein digestibility increased with decreasing feed moisture.
The influence of pinto bean flour and processing moisture on the physical properties and in vitro digestibility of rice-bean extrudates has been investigated. Brown rice: pinto bean flour (0%, 15%, 30%, and 45% bean flour) were extruded under 5 moisture conditions (17.2%, 18.1%, 18.3%, 19.5%, and 20.1%). Physical properties bulk density, unit density, radial expansion, axial expansion, overall expansion, specific volume, hardness, color, water solubility index, and water absorption index and in vitro starch and protein digestibilities were determined. Increasing bean flour and processing moisture increased density and hardness while decreasing expansion. Rapidly digestible starch decreased and resistant starch increased as bean substitution and processing moisture increased. In vitro protein digestibility increased with increasing bean flour or with decreasing processing moisture. Incorporating bean flour into extruded snacks can negatively affect physical attributes (hardness, density, and expansion) while positively affecting in vitro starch (decrease) and protein (increase) digestibilities.
The effect of high pressure processing (HPP) at 200 to 600 MPa for 2.5 or 5 min on physicochemical properties (color, pH, titratable acidity, total soluble solids content/TSSC, pulp content, particle ...size distribution, and viscosity), microbial counts (aerobic bacteria, yeast and mold counts), bioactive compounds (total phenolic and anthocyanin contents), and antioxidant capacities (DPPH radical scavenging capacity and ferric reducing antioxidant power) of aronia berry purée were investigated. All measurements were compared between HPP treated and untreated purées. TSSC and viscosity decreased significantly when pressurized above 400 MPa for 2.5 min and at all HPP conditions, respectively. Other physicochemical properties changed insignificantly after HPP. Pressurization at 400 and 600 MPa both effectively reduced yeasts and molds to below 1 log CFU/g, and reduced aerobic bacteria to <2 log CFU/g only when pressurized for 5 min. No significant reduction in phenolic contents or antioxidant capacities in pressurized purée was observed.
Purée is a feasible form of aronia berry used as food product, considering the astringent taste of whole aronia berry. The results of this study suggest that HPP will significantly reduce the microbial counts of aronia berry purée, while retaining antioxidant capacities and most physicochemical properties of aronia berry purée. The outcomes could help the food industry apply HPP to the commercial production of aronia berry purée-based food products to meet the quality standards with safety ensured.
•High pressure processing (HPP) on aronia purée was studied for the first time.•Four-hundred and 600 MPa for 5 min inactivated spoilage microbes.•Total phenolics and anthocyanins were preserved in aronia purée after HPP.•Phenolic antioxidant capacities in aronia purée were unaffected by HPP.•HPP did not affect most physicochemical properties of aronia purée.
The objective of this work was to determine the impact of extrusion variables moisture (17–25%), screw speed (170–250 r.p.m.) and temperature (90–150 °C) on the physical properties and antioxidant ...activity of proso millet extrudates. Extrusion variables were adjusted using an inscribed central composite rotatable design. Response variables were bulk density (BD), radial expansion ratio, water absorption index, water solubility index, hardness, colour (L*, a*, b*) and antioxidant activity. Moisture and screw speed were the most influential variables affecting millet extrusion: their linear, quadratic and interaction terms accounted for more than 50% of the variability in all responses except for b*. Expansion was greatest at severe conditions of low moisture and high screw speed. These conditions were also consistent with the highest antioxidant activity. This study demonstrated that high expansion and antioxidant activity can be obtained by extruding proso millet under low moisture and high screw speed conditions.
The dietary fiber in wheat bran, principally non-starch polysaccharides (NSP), is mostly water-unextractable and is poorly utilized by human gut microbiota. The purpose of this study was to determine ...the change in water-extractability of NSP in wheat bran upon extrusion and then to determine if extrusion impacts the availability of NSP for fermentation by the fecal microbiota during in vitro fecal fermentation. A secondary objective was to incorporate extruded bran into a product formulation to determine if changes in WE-NSP and NSP fermentation were maintained in a finished product. Bran was extruded using combinations of high or low moisture (15% and 30% wb) and high or low screw speed (120 and 250rpm). All extrusion conditions resulted in increases in WE-NSP and fecal microbiota short chain fatty acid (SCFA) production upon fermentation compared with unextruded bran. Low screw speed and low moisture resulted in the greatest increase in WE-NSP (3-fold) as well as the highest production of SCFA during fermentation (1.4-fold) compared with unextruded bran. Whole wheat breads containing extruded bran did not show increases in either WE-NSP or SCFA production compared with the control. In conclusion, extrusion of wheat bran increased WE-NSP, which enabled greater fermentability by human fecal microbiota. However, once extruded bran was used in a whole wheat bread formulation the changes in fermentation outcomes were no longer evident.
•Extrusion resulted in increased water-extractable non-starch polysaccharide extractability in wheat bran.•Extrusion resulted in increased non-starch polysaccharide fermentation in short chain fatty acids during fermentation.•Extrusion increases short chain fatty acid production during fermentation.•These effects were no longer clearly evident when extruded bran was incorporated into bread.
Extrusion exposes flour components to high pressure and shear during processing, which may affect the dietary fiber fermentability by human fecal microbiota. The objective of this study was to ...determine the effect of flour moisture content during extrusion on in vitro fermentation properties of whole grain oats. Extrudates were processed at three moisture levels (15%, 18%, and 21%) at fixed screw speed (300rpm) and temperature (130°C). The extrudates were then subjected to in vitro digestion and fermentation. Extrusion moisture significantly affected water-extractable β-glucan (WE-BG) in the extrudates, with samples processed at 15% moisture (lowest) and 21% moisture (highest) having the highest concentration of WE-BG. After the first 8h of fermentation, more WE-BG remained in fermentation media in samples processed at 15% moisture compared with the other conditions. Also, extrusion moisture significantly affected the production of acetate, butyrate, and total SCFA by the microbiota during the first 8h of fermentation. Microbiota grown on extrudates processed at 18% moisture had the highest production of acetate and total SCFA, whereas bacteria grown on extrudates processed at 15% and 18% moisture had the highest butyrate production. After 24h of fermentation, samples processed at 15% moisture supported lower Bifidobacterium counts than those produced at other conditions, but had among the highest Lactobacillus counts. Thus, moisture content during extrusion significantly affects production of fermentation metabolites by the gut microbiota during the initial stages of fermentation, while also affecting probiotic bacteria counts during extended fermentation.
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•Whole grain oats were extruded at 3 moisture contents•Lower moisture led to more water-extractable beta-glucan•Lower moisture resulted in more butyrate during initial stage of fecal fermentation•Lower moisture supported lower Bifidobacterium after 24h of fermentation•Higher moisture supported lower Lactobacillus after 24h of fermentation
Aronia berry puree was subjected to 400 and 600 MPa, 5 min high pressure processing (HPP) and then microbial shelf-life and quality changes of aronia puree during 8-week refrigerated storage were ...evaluated. HPP reduced the aerobic plate counts (APC) significantly and APC changed insignificantly during the 8-week storage. HPP completely inactivated yeasts and molds, and no regrowth was observed during 8-week storage. In contrast, yeasts in untreated puree increased from 4.7 to 6.1 log CFU/g. Physicochemical properties, total phenolic contents and antioxidant capacities of aronia puree had insignificant changes right after HPP and during 8-week refrigerated storage. Total anthocyanin content of untreated samples and those treated at 400 MPa decreased continuously during the storage. HPP, especially processing at 600 MPa for 5 min, could be an effective preservation technique for microbial population reduction, quality retention, and shelf-life extension of aronia puree.
The growing demand for minimal processed and antioxidant-rich aronia berry products has stimulated the interest of food industry. Industrial sector demands methods to extend the microbial shelf-life and maintain its quality and nutritional values of aronia berry products during refrigerated storage. The results of this study demonstrated that HPP is effective in extending the microbial shelf-life, maintaining the quality and preserving the bioactive antioxidants of aronia berry puree during 8 weeks of refrigerated storage.
A microsphere immunoassay (MIA) utilising Luminex xMap technology that is capable of determining leptospirosis IgG and IgM independently was developed. The MIA was validated using 200 human samples ...submitted for routine leptospirosis serology testing. The traditional microscopic agglutination (MAT) method (now 100 years old) suffers from a significant range of technical problems including a dependence on antisera which is difficult to source and produce, false positive reactions due to auto-agglutination and an inability to differentiate between IgG and IgM antibodies. A comparative validation method of the MIA against the MAT was performed and used to determine the ability of the MIA to detect leptospiral antibodies when compared with the MAT. The assay was able to determine samples in the reactive, equivocal and non-reactive ranges when compared to the MAT and was able to differentiate leptospiral IgG antibodies from leptospiral IgM antibodies. The MIA is more sensitive than the MAT and in true infections was able to detect low levels of antibody in the later stages of the acute phase as well as detect higher levels of IgM antibody earlier in the immune phase of the infection. The relatively low cost, high throughput platform and significantly reduced dependency on large volumes of rabbit antisera make this assay worthy of consideration for any microbiological assay that currently uses agglutination assays.
Leptospirosis is a globally important cause of acute febrile illness, and a common cause of non-malarial fever in Asia, Africa, and Latin America. Simple rapid diagnostic tests (RDTs) are needed to ...enable health-care workers, particularly in low resource settings, to diagnose leptospirosis early and give timely targeted treatment. This study compared four commercially available RDTs to detect human IgM against
spp. in a head-to-head prospective evaluation in Mahosot Hospital, Lao PDR. Patients with an acute febrile illness consistent with leptospirosis (
= 695) were included in the study during the 2014 rainy season. Samples were tested with four RDTs: ("Test-it" Life Assay, Cape Town, South Africa;
= 418; "Leptorapide" Linnodee, Ballyclare, Northern Ireland;
= 492; "Dual Path Platform" DPP Chembio, Medford, NY;
= 530; and "SD-IgM" Standard Diagnostics, Yongin, South Korea;
= 481). Diagnostic performance characteristics were calculated and compared with a composite reference standard combining polymerase chain reaction (PCR) (
), microscopic agglutination tests (MATs), and culture. Of all patients investigated, 39/695 (5.6%) were positive by culture, PCR, or MAT. The sensitivity and specificity of the RDTs ranged greatly from 17.9% to 63.6% and 62.1% to 96.8%, respectively. None of the investigated RDTs reached a sensitivity or specificity of > 90% for detecting
infections on admission. In conclusion, our investigation highlights the challenges associated with
diagnostics, particularly in populations with multiple exposures. These findings emphasize the need for extensive prospective evaluations in multiple endemic settings to establish the value of rapid tools for diagnosing fevers to allow targeting of antibiotics.
While limbal epithelial cells are used for treating ocular surface wounds, the therapeutic potential of mesenchymal cells cultivated from the limbal stroma (LMSC) is less clear. We have therefore ...examined the effects of LMSC when applied to acute ocular surface wounds. LMSC derived from male rabbits (RLMSC) were applied to the ocular surface of female rabbits immediately following removal of the corneal and limbal epithelium. Human amniotic membrane (HAM) was used as the vehicle for implanting the RLMSC. The effects of RLMSC were examined when applied alone (n = 3) and in conjunction with a stratified culture of human limbal epithelial cells (HLE) grown on the opposing surface of the HAM (n = 3). Outcomes were monitored over 3 months in comparison with animals receiving no treatment (n = 3) or treatment with HLE alone on HAM (n = 3). Animals treated with RLMSC (n = 6) displayed faster re-epithelialization (∼90% versus 70% healing after 12 weeks), with best results being observed when RLMSC were pre-cultivated and implanted in the presence of HLE (p < 0.01; 90% healing by 7 weeks). While all animals displayed conjunctival cells on the corneal surface (by presence of goblet cells and/or keratin 13 expression) and corneal neovascularization, evidence of corneal epithelial regeneration was observed in animals that received RLMSC in the presence of HLE (by staining for keratin 3 and the absence of goblet cells). Conversely, corneal neovascularization was significantly greater when RLMSC were applied in the absence of HLE (<0.05; 90% of cornea compared with 20–30% in other cohorts). Nevertheless, neither human nuclear antigen nor rabbit Y chromosome were detected within the regenerated epithelium. Our results demonstrate that while cultured LMSC encourage corneal re-epithelialization, healing is improved by the pre-cultivation and implantation of these mesenchymal cells in the presence of limbal epithelial cells.
Leptospirosis is an important zoonosis worldwide, with infections occurring after exposure to contaminated water. Despite being a global problem, laboratory diagnosis remains difficult with culture ...results taking up to 3 months, serology being retrospective by nature, and polymerase chain reaction showing limited sensitivity. Leptospira have been shown to survive and multiply in blood culture media, and we hypothesized that extracting DNA from incubated blood culture fluid (BCF), followed by quantitative real-time polymerase chain reaction (qPCR) could improve the accuracy and speed of leptospira diagnosis. We assessed this retrospectively, using preincubated BCF of Leptospira spp. positive (N= 109) and negative (N= 63) febrile patients in Vientiane, Lao PDR. The final method showed promising sensitivities of 66% (95% confidence interval CI: 55-76) and 59% (95% CI: 49-68) compared with direct or direct and indirect testing combined, as the respective reference standards (specificities > 95%). Despite these promising diagnostic parameters, a subsequent prospective evaluation in a Lao hospital population (N= 352) showed that the sensitivity was very low (∼30%) compared with qPCR on venous blood samples. The disappointingly low sensitivity does suggest that venous blood samples are preferable for the clinical microbiology laboratory, although BCF might be an alternative if leptospirosis is only suspected postadmission after antibiotics have been used.
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