Starch, composed of amylose (AMY) and amylopectin (AP), is a common constituent of many agricultural grain crops and the main source of energy for both humans and domesticated animals. There are ...several physiochemical factors that determine the suitability of starch for a specific end use, which mainly entails the ratios of the AMY and AP, but also the granular and molecular structure thereof. This, in turn, determines its functional properties, i.e. swelling, gelatinisation, pasting and retrogradation. Different instruments, such as the Amylograph®, Falling Number® System, Ottawa Starch Viscometer and the Consistometer, in addition to the more recently developed Rapid Visco Analyser (RVA) are used to study the functional properties of starch. Due to its reliability, repeatability and versatility, the RVA is increasingly used to determine the physiochemical and, in particular, the pasting properties of cereal starches. This review gives an update on the current knowledge of starch-related physiochemical and functional properties of a selection of cereal (i.e. wheat, barley, rice and maize) starches, and the RVA as a measuring instrument thereof, including critical analysis and discussion.
Brewing is an ancient process which started in the middle east over 10,000 years ago. The style of beer varies across the globe but modern brewing is very much the same regardless of the style. While ...there are thousands of compounds in beer, current methods of analysis rely mostly on the content of only several important processing parameters such as gravity, bitterness, or alcohol. Near infrared and mid infrared spectroscopy offer opportunities to predict dozens to hundreds of compounds simultaneously at different stages of the brewing process. Importantly, this is an opportunity to move deeper into quality through measuring wort and beer composition, rather than just content. This includes measuring individual sugars and amino acids prior to fermentation, rather than total °Plato or free amino acids content. Portable devices and in-line probes, coupled with more complex algorithms can provide real time measurements, allowing brewers more control of the process, resulting in more consistent quality, reduced production costs and greater confidence for the future.
•High-amylose wheat has an eight-fold increase of resistant starch content in noodle.•Cooked noodles contain two distinct forms of protein-starch matrix.•A reductionist approach is used to study the ...role of the matrix in starch digestion.•Protein removal leads to higher digestion rate constants in raw and cooked flours.•Higher food integrity in HAW noodles enhances the resistance against digestion.
Wheat flour, consisting of a complex matrix of starch and protein, is used as a representative model of whole food here to investigate the binary interaction in relation to amylose level and hydrothermal treatment in noodles as a food exemplar. Noodle made of high-amylose wheat (HAW) flour showed an eight-fold higher resistant starch content, compared to the wild type. Protein removal under simulated intestinal digestion conditions resulted in higher starch digestion rate coefficients in raw and cooked flours. In cooked flours, the substrate becomes similarly accessible to digestive enzymes regardless of protein removal. The results indicate that the increased protein content in native HAW flour and thermal stability of starch in HAW noodles lead to higher food integrity and consequently enhance the resistance against α-amylase digestion. Overall, the study suggests that a diversity of starch-protein interactions in wheat-based food products underlies the nutritional value of natural whole foods.
•Kinetic and microscopic study showing how barley protein affects starch degradation.•Protein inhibits enzymatic degradation through several mechanisms.•Protein-enzyme binding interaction is the main ...reason.
The conversion of barley starch to sugars is a complex enzymic process. Most previous work concerned the biotechnical aspect of in situ barley enzymes. However, the interactions among the macromolecular substrates and their effects on enzymic catalysis has been little examined. Here, we explore the mechanisms whereby interactions of protein and starch in barley flour affect the kinetics of enzymatic hydrolysis of starch in an in vitro system, using digestion rate data and structural analysis by confocal microscopy. The degradation kinetics of both uncooked barley flour and of purified starches are found to be two-step sequential processes. Barley proteins, especially the water-soluble component, are found to retard the digestion of starch degraded by α-amylase: the enzyme binds with water-insoluble protein and with starch granules, leading to reduced starch hydrolysis. These findings are of potential industrial value in both the brewing and food industries.
Cereal grains have been domesticated largely from food grains to feed and malting grains. Barley (
) remains unparalleled in its success as a primary brewing grain. However, there is renewed interest ...in "alternative" grains for brewing (and distilling) due to attention being placed on flavor, quality, and health (i.e., gluten issues) aspects that they may offer. This review covers basic and general information on "alternative grains" for malting and brewing, as well as an in-depth look at several major biochemical aspects of these grains including starch, protein, polyphenols, and lipids. These traits are described in terms of their effects on processing and flavor, as well as the prospects for improvement through breeding. These aspects have been studied extensively in barley, but little is known about the functional properties in other crops for malting and brewing. In addition, the complex nature of malting and brewing produces a large number of brewing targets but requires extensive processing, laboratory analysis, and accompanying sensory analysis. However, if a better understanding of the potential of alternative crops that can be used in malting and brewing is needed, then significantly more research is required.
Molecular structure of whole and debranched barley starch has been characterized.Correlations found between protein content, starch molecular structure & grain size.Starch structure offers an ...improved way to choose grains for brewing quality.Target functional properties include more fermentable sugars, less limit dextrins.
Correlations among barley protein, starch molecular structure and grain size were determined using 30 barley samples with variable protein contents. Starch molecular structure was characterized by fluorophore-assisted carbohydrate electrophoresis and by size-exclusion chromatography (SEC, also termed GPC). The chain-length distributions of amylopectin were fitted using a mathematical model reflecting the relative activities of starch branching enzymes and starch synthase enzymes. Increased protein content significantly and negatively correlated with higher amounts of amylose with longer chains (degree of polymerization, DP 1600⿿40000) while barley grain sizes positively associated with starch contents. Protein content also positively correlated with the proportion of longer chains of amylopectin (DP 34⿿100). These results showed that the enzyme activities of starch synthases change with protein content, leading to altered starch contents, structures and grain sizes. From this perspective, selecting for large grain size (or low protein content) does not necessarily relate to starch structure, although may suggest long chains of amylopectin. Measuring starch structure could give a good indication of process performance in human food, animal feed and brewing, as all these structural features contribute to significant functional properties.
Sorghum (Sorghum bicolor), a grass native to Africa, is a popular alternative to barley for brewing beer. The importance of sorghum to beer brewing is increasing because it is a naturally gluten-free ...cereal, and climate change is expected to cause a reduction in the production of barley over the coming decades. However, there are challenges associated with the use of sorghum instead of barley in beer brewing. Here, we used proteomics and metabolomics to gain insights into the sorghum brewing process to advise processes for efficient beer production from sorghum. We found that during malting, sorghum synthesizes the amylases and proteases necessary for brewing. Proteomics revealed that mashing with sorghum malt required higher temperatures than barley malt for efficient protein solubilization. Both α- and β-amylase were considerably less abundant in sorghum wort than in barley wort, correlating with lower maltose concentrations in sorghum wort. However, metabolomics revealed higher glucose concentrations in sorghum wort than in barley wort, consistent with the presence of an abundant α-glucosidase detected by proteomics in sorghum malt. Our results indicate that sorghum can be a viable grain for industrial fermented beverage production, but that its use requires careful process optimization for efficient production of fermentable wort and high-quality beer.
The use of near infrared (NIR) hyperspectral imaging and hyperspectral image analysis for distinguishing between hard, intermediate and soft maize kernels from inbred lines was evaluated. NIR ...hyperspectral images of two sets (12 and 24 kernels) of whole maize kernels were acquired using a Spectral Dimensions MatrixNIR camera with a spectral range of 960–1662
nm and a sisuChema SWIR (short wave infrared) hyperspectral pushbroom imaging system with a spectral range of 1000–2498
nm. Exploratory principal component analysis (PCA) was used on absorbance images to remove background, bad pixels and shading. On the cleaned images, PCA could be used effectively to find histological classes including glassy (hard) and floury (soft) endosperm. PCA illustrated a distinct difference between glassy and floury endosperm along principal component (PC) three on the MatrixNIR and PC two on the sisuChema with two distinguishable clusters. Subsequently partial least squares discriminant analysis (PLS-DA) was applied to build a classification model. The PLS-DA model from the MatrixNIR image (12 kernels) resulted in root mean square error of prediction (RMSEP) value of 0.18. This was repeated on the MatrixNIR image of the 24 kernels which resulted in RMSEP of 0.18. The sisuChema image yielded RMSEP value of 0.29. The reproducible results obtained with the different data sets indicate that the method proposed in this paper has a real potential for future classification uses.
Beer for live microbe delivery Ramanan, Maany; Fox, Glen P; Marco, Maria L
Journal of functional foods,
February 2024, 2024-02-00, 2024-02-01, Letnik:
113
Journal Article
Recenzirano
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•Beer can serve as medium for live microbe and probiotic delivery.•Sustained live cell count throughout beer shelf-life is a challenge.•Probiotic beer can be made with probiotic ...yeasts, bacteria or both.•Mixed-species communities are not fully explored in beer.
There is growing interest in the potential of probiotics and other commensal dietary microbes to improve human health. This review will examine beer as a microbe-containing food and the considerations needed when using beer for probiotic and other live microbe delivery to the digestive tract. Although most beers harbor low numbers of live microbes after brewing is complete and the final product is an environmentally stressful environment which impairs long-term microbial survival, commercially-produced Lambic and sour beers can contain live microbes. Recent studies have also tested the viability and impacts of probiotic strains of Saccharomyces and lactobacilli strains in beer. The findings show there remains the need to adjust strain use and production practices to enable microbial growth and survival throughout the intended shelf-life. We discuss opportunities to increase microbial survival overall, as well as for strains that confer specific health benefits.
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