Indigenous Australian grass seeds as grains: macrostructure, microstructure and histochemistry.

Utilization of grains of local grasses by Australia's First Nations people for food and connection to Country has largely been lost due to colonization. Native Australian grain production has the potential to deliver environmental, economic, nutritional and cultural benefits to First Nations people and the wider community. Revitalization of the native grain food system can only be achieved if relevant properties of the grains are elucidated. This study aimed to characterize the grain structure and histochemistry of four Australian native grasses: Dactyloctenium radulans (Button Grass), Astrebla lappacea (Curly Mitchell Grass), Panicum decompositum (Native Millet) and Microlaena stipoides (Weeping Grass). For these species, as well as wheat and sorghum, whole-grain images were obtained via stereo microscopy, starch and the embryo were visualized, and sections of fixed grains were imaged via bright-field and fluorescence microscopy. The shape, size and colour of the whole native grains varied between the species. The aleurone layer was one-cell thick in the native species, as in the domesticated grains, except for Weeping Grass, which had a two-cell-thick aleurone. In the native grains, endosperm cell walls appeared thinner than in wheat and sorghum. Starch granules in Button Grass, Curly Mitchell Grass and Native Millet were found mainly in the central region of the starchy endosperm, with very few granules in the sub-aleurone layer, whereas Weeping Grass had abundant starch in the sub-aleurone. Protein appeared most abundant in the aleurone and sub-aleurone layers of the native grains, although in Button Grass, the starchy endosperm was observed to be rich in protein, as in wheat and sorghum. As a proportion of the whole grain, the embryo was larger in the native species than in wheat. The differences found in the grain properties among the four native Australian species have important implications for the agri-food industry in a changing climate.

Panicum decompositum, an Australian Native Grass, Has Strong Potential as a Novel Grain in the Modern Food Market.

Native Millet (Panicum decompositum) is a native grass species that was used as a staple food by many Australian Aboriginal communities. In this study, the potential for using Native Millet (NM) as a novel flour in the modern food market was investigated. Intact grain and white and wholemeal flours from two populations of NM were compared to bread wheat cv. Spitfire (SW) using a range of physical and chemical tests. The baking properties of NM flour were assessed using basic flatbreads made with 25:75 and 50:50 (NM:SW) mixes of wholemeal flour with 100% SW wholemeal flour used as the control. The grain size of NM was found to be smaller than SW. Milling yield, defined as the proportion of flour obtained from a whole seed, for NM was 4-10% lower than SW under the same moisture conditions used for tempering (drying) wheat. The properties of wholemeal flour indicated that NM flour has lower viscosity and low flour pasting ability compared to SW. This is likely due to the low starch content and high fibre content of NM seed. Wholemeal flour derived from NM had a protein content of 13.6% compared to 12.1% for SW. Based on a sensory analysis using an untrained panel, the distinct colour and texture may negatively affect the acceptance of NM flour by the consumer, but taste and aroma was not found to differ among samples. There were strong indications that the novelty of NM flour may help outweigh any limitations to consumer acceptance, making it a valuable product in future food markets.

An eco-friendly chitosan/cellulose acetate hybrid nanostructure containing Ziziphora clinopodioides essential oils for active food packaging applications.

This work presents the fabrication and characterization of a hybrid nanostructure, Ziziphora clinopodioides essential oils (ZEO)-loaded chitosan nanoparticles (CSNPs-ZEO) embedded into cellulose acetate (CA) nanofibers (CA-CSNPs-ZEO). The CSNPs-ZEO were first synthesized through the ionic gelation method. Then, through simultaneous electrospraying and electrospinning processes, the nanoparticles were embedded in the CA nanofibers. The morphological and physicochemical characteristics of the prepared nanostructures were evaluated using different methods, including scanning electron microscopy (SEM), water vapor permeability (WVP), moisture content (MC), mechanical testing, differential scanning calorimetry (DSC), and release profile studies. The antibacterial activity of the nanostructures was explored on raw beef as a food model during 12 days of storage at 4 °C. The obtained results indicated the successful synthesis of CSNPs-ZEO nanoparticles with an average size of 267 ± 6 nm and their incorporation into the nanofibers matrix. Moreover, the CA-CSNPs-ZEO nanostructure showed a lower water vapor barrier and higher tensile strength compared with ZEO-loaded CA (CA-ZEO) nanofiber. The CA-CSNPs-ZEO nanostructure also exhibited strong antibacterial activity, which effectively extended the shelf-life of raw beef. The results demonstrated a strong potential for innovative hybrid nanostructures in active packaging to maintain the quality of perishable food products.

Sorghum in foods: Functionality and potential in innovative products.

Sorghum grain is a staple food for about 500 million people in 30 countries in Africa and Asia. Despite this contribution to global food production, most of the world's sorghum grain, and nearly all in Western countries, is used as animal feed. A combination of the increasingly important ability of sorghum crops to resist heat and drought, the limited history of the use of sorghum in Western foods, and the excellent functional properties of sorghum grain in healthy diets, suggests a greater focus on the development of new sorghum-based foods. An understanding of the structural and functional properties of sorghum grain to develop processes for production of new sorghum-based foods is required. In this review, we discuss the potential of sorghum in new food products, including sorghum grain composition, the functional properties of sorghum in foods, processing of sorghum-based products, the digestibility of sorghum protein and starch compared to other grains, and the health benefits of sorghum. In the potential for sorghum as a major ingredient in new foods, we suggest that the gluten-free status of sorghum is of relatively minor importance compared to the functionality of the slowly digested starch and the health benefits of the phenolic compounds present.

Starch digestion rates in multiple samples of commonly used feed grains in diets for broiler chickens.

In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains (sorghum, wheat, maize, barley, triticale) were determined. The methodology to determine starch digestion rates in poultry is detailed herein. Starch digestion rates were not significantly different (P = 0.128) across the 18 feed grains, which reflects the wide variations that were observed within a given feedstuff. Nevertheless, starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0% (0.117 versus 0.075 min-1; P = 0.012) than their sorghum-based counterparts on the basis of a pair-wise comparison. In descending order, the following starch digestion rates were observed: wheat (0.117 min-1), barley (0.104 min-1), triticale (0.093 min-1), maize (0.086 min-1), sorghum (0.075 min-1). The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.

Capping dietary starch:protein ratios in moderately reduced crude protein, wheat-based diets showed promise but further reductions generated inferior growth performance in broiler chickens.

The hypothesis that capping dietary starch:protein ratios would enhance the performance of broiler chickens offered reduced-crude protein (CP) diets was tested in this experiment. A total of 432 off-sex, male Ross 308 chicks were allocated to 7 dietary treatments from 7 to 35 d post-hatch. The experimental design consisted of a 3 × 2 factorial array of treatments with the seventh treatment serving as a positive control. Three levels of dietary CP (197.5, 180.0 and 162.5 g/kg) with either uncapped or capped dietary starch:protein ratios constituted the factorial array of treatments, whilst the positive control diet contained 215.0 g/kg CP. The positive control diet had an analysed dietary starch:protein ratio of 1.50 as opposed to a ratio of 1.68 in the uncapped 197.5 g/kg CP diet and 1.41 in the corresponding capped diet and the capped 197.5 g/kg CP diet displayed promise. The growth performance this diet matched the positive control but outperformed the uncapped 197.5 g/kg CP diet by 10.4% (2,161 vs. 1,958; P = 0.009) in weight gain, by 3.10% (3,492 vs. 3,387; P = 0.019) in feed intake on the basis of pair-wise comparisons and numerically improved FCR by 4.04% (1.616 vs. 1.684). However, the growth performance of birds offered the 180.0 and 162.5 g/kg CP dietary treatments was remarkably inferior, irrespective of dietary starch:protein ratios. This inferior growth performance was associated with poor feathering and even feather-pecking and significant linear relationships between feather scores and parameters of growth performance were observed. The amino acid profile of feathers was determined where cysteine, glutamic acid, glycine, proline and serine were dominant in a crude protein content of 931 g/kg. Presumably, the feathering issues observed were manifestations of amino acid inadequacies or imbalances in the more reduced-CP diets and consideration is given to the implications of these outcomes.

Impacts of reduced-crude protein diets on key parameters in male broiler chickens offered maize-based diets.

A total of 294 male, off-sex Ross 308 chickens were offered 7 dietary treatments with crude protein (CP) contents of 210, 195, 180, and 165 g/kg. One of the four 165 g/kg diet was consistent with the higher protein diets and 3 were modified to investigate the effects of increased methionine levels, pre-pellet inclusion of whole maize, and whey protein concentrate in reduced-CP broiler diets. There were 7 replicate cages, 6 birds per cage, from 14 to 35 D post-hatch. The average feed conversion ratio (FCR) of birds offered 210, 195, 180 g/kg CP diets was 1.555 which was superior (P < 0.05) to the 1.608 FCR of their 165 g/kg counterparts. The transition from 210 to 165 g/kg (diet 4) CP diets linearly increased (P < 0.001) relative fat-pad weights from 8.64 to 14.62 g/kg. The same transition linearly increased jejunal and ileal starch digestibility coefficients (P < 0.001), metabolizable to gross energy ratios (ME:GE) ratios (P < 0.001) and nitrogen (N)-corrected apparent metabolizable energy (AMEn) (P = 0.001) but did not influence N retention. Starch:protein disappearance rate ratios increased linearly (P < 0.001) from 2.68 to 3.82 in the jejunum and from 1.76 to 2.94 in the ileum following dietary CP reductions. Ileal disappearance rate ratios were quadratically related to FCR (r = 0.486; P < 0.005) and linearly related to relative fat-pad weights (r = 0.663; P < 0.001) where both parameters were disadvantaged by widening ratios. The transition from 210 to 165 g/kg crude protein diets linearly increased the average digestibility coefficient of 17 amino acids from 0.459 to 0.594 in jejunum and from 0.744 to 0.790 in the ileum. The present study demonstrates that dietary CP can be reduced from 210 to 180 g/kg without negatively influencing broiler performance but the further reduction to 165 g/kg compromised FCR. However, the three modifications to the 165 g/kg CP diet failed to enhance broiler performance.

Effects of reduced crude protein levels, dietary electrolyte balance, and energy density on the performance of broiler chickens offered maize-based diets with evaluations of starch, protein, and amino acid metabolism.

The crude protein (CP) content of 4 iso-energetic, maize-based diets containing 11.00 g/kg digestible lysine was reduced in gradations from 200 to 156 g/kg with increasing inclusions of synthetic, or unbound, essential amino acids. A constant dietary electrolyte balance (DEB) of 230 mEq/kg was maintained, but a second 156 g/kg CP diet had a DEB of 120 mEq/kg, and energy densities of the 156 g/kg CP diet were reduced in the sixth and seventh treatments. Each of the 7 dietary treatments were offered to 7 replicate cages (6 birds/cage) or a total of 294 Ross 308 off-sex male broilers from 14 to 35 D posthatch. Reductions in CP from 200 to 156 g/kg did not influence weight gain but quadratically increased feed conversion ratio (FCR) and linearly increased relative abdominal fat-pad weights and feed intakes. The reduction in DEB did not influence growth performance but did adversely influence some amino acid digestibilities. Reducing energy density by 100 kcal/kg did not influence growth performance of birds offered the 156 g/kg CP diet but numerically reduced fat-pad weights. The transition from 200 to 156 g/kg CP diets generally enhanced jejunal and ileal amino acid digestibility coefficients but had diverse effects on free amino acid concentrations in systemic plasma with a remarkable 116% increase in threonine. Starch:protein disappearance rate ratios linearly increased in the jejunum and the ileum following the same transition, and these expanding ratios were related to heavier fat-pads and compromised FCR. This study indicates that reductions in dietary CP from 200 to 172 g/kg supported by inclusions of unbound essential amino acids do not compromise growth performance, but a further reduction to 156 g/kg CP significantly increased FCR. Both heavier relative fat-pad weights and inferior FCR were related to expanding starch:protein disappearance rate ratios, which suggests condensed dietary starch:protein ratios may advantage birds offered reduced CP diets.

Dietary starch to lipid ratios influence growth performance, nutrient utilisation and carcass traits in broiler chickens offered diets with different energy densities.

Twelve experimental diets with three levels of energy densities (11.25, 12.38 and 13.50 MJ/kg) and fours levels of starch to lipid ratios (14:1, 12:1, 7:1, 4:1) were offered to 288 male Ross 308 broiler chickens. All the diets were formulated to contain consistent digestible lysine to metabolisable energy ratios (0.87 g digestible lysine/MJ AMEn) and ideal amino acid ratios. Growth performance was monitored from 7 to 27 days post-hatch and parameters of nutrient utilisation (AME, AMEn, AME:GE ratios, N retention) were determined from 24 to 26 days post-hatch. Apparent protein (N) and starch digestibility coefficients, carcass yield and composition were determined at 27 days post-hatch. There were no interactions between energy densities and starch to lipid ratios on growth performance and carcass weights (P > 0.05). Feed intake was reduced with increased energy densities (P < 0.001). Weight gain and FCR were improved with increased dietary energy densities (P < 0.0001). Starch to lipid ratios linearly increased weight gain (r = 0.448, P = 0.001) and feed intake (r = 0.509, P < 0.001) without influencing FCR (P > 0.75). Both nutrient densities and starch to lipid ratios significantly impacted on carcass weight and yield. Heavier carcass weights and higher yields were observed in broiler chickens offered diets with high nutrient density (P ≤ 0.001). Carcass weight (r = 0.441, P < 0.005) was positively correlated with starch to lipid ratios and this tended to be the case for carcass yield (r = 0.277, P = 0.057) too. However, there were interactions on lipid concentrations in carcass (P < 0.001) as broiler chickens offered diet containing the lowest nutrient density and the highest starch to lipid ratio had the highest lipid carcass concentration of 12.94%. In conclusion, protein and energy need to be considered in tandem in practical diet formulation, especially in diets containing high crystalline amino acid inclusions. The impact of lipid on feed intake and starch on carcass lipid concentrations should also be taken into consideration.

Outlook: Sorghum as a feed grain for Australian chicken-meat production.

This review is an outlook for sorghum as a feed grain for broiler chickens based on a survey of relevant stake-holders and recent research outcomes. Australian grain sorghum production will probably continue to generate a harvest in the order of 2.5 × 106 t of which some 7.9 × 105 t will be used as a feed grain for poultry and pigs. Feed grains are included primarily to provide energy from starch, but energy utilisation by broiler chickens offered sorghum-based diets is relatively inferior, because of incomplete starch digestion. Kafirin, the dominant protein fraction, 'non-tannin' phenolic compounds and phytate are 3 'starch extrinsic' factors in sorghum that compromise starch digestibility and energy utilisation in broiler chickens offered sorghum-based diets. Kafirin concentrations in 6 sorghum varieties were negatively correlated with metabolizable energy to gross energy (ME:GE) ratios (r = -0.891; P < 0.02) or the efficiency of energy utilisation in broiler chickens. Importantly, kafirin proportions of sorghum protein may be increasing with time in Australia. If so, this represents a fundamental challenge to sorghum breeders which presumably could be met by the development of sorghum varieties with different characteristics, especially in relation to the γ- and ß-kafirin fractions. White sorghum varieties contain lower polyphenol concentrations which should be advantageous as concentrations of total phenolic compounds were negatively correlated to ME:GE ratios (r = -0.838; P < 0.04) in 6 sorghum varieties. It would be desirable if more white varieties were to become available. It is suggested that responses to exogenous phytase in birds offered sorghum-based diets would be more robust if sorghum were to contain lower concentrations of kafirin and phenolic compounds. Paradoxically, while better sorghum varieties almost certainly could be developed, it may not necessarily follow that they will command a price premium from poultry and pig producers.

Effects of Sorghum Malting on Colour, Major Classes of Phenolics and Individual Anthocyanins.

Sorghum (Sorghum bicolor) grain contains many health-promoting phytochemicals, including a broad range of phenolic compounds. Malting of cereal grains is known to increase the bioavailability of macro- and micronutrients. However, the detailed effects of malting on sorghum grain anthocyanins, a major class of phenolics that influence the taste and colour of sorghum-based foods, requires further investigation. Eight commercial sorghum hybrids harvested from three regions in eastern Australia were malted and analysed for colour, tannin content, total phenolic content (TPC), flavan-4-ols, total flavonoids, total anthocyanins and 3-deoxyanthocyanins. Grains of all the sorghums were found to be tannin-free. Malting decreased the TPC of all samples. For TPC, the grand means among all the sorghum cultivars for raw and malted grain were 2.77 and 2.48 mg gallic acid equivalents (GAE)/g, respectively. For flavan-4-ols, the grand means for raw and malted sorghum grains were 2.98 and 2.23 abs/mL/g, respectively. Remarkably, total anthocyanin levels more than doubled upon malting whereas total flavonoid levels decreased by 12%. The average abundance of 3-deoxyanthocyanins in raw sorghum grains increased for about 8-fold upon malting. Our results will be valuable for sorghum breeders in the selection of lines for specific end uses and for food scientists developing sorghum-based products.

The potential of rapid visco-analysis starch pasting profiles to gauge the quality of sorghum as a feed grain for chicken-meat production.

Thirteen extensively characterised grain sorghum varieties were evaluated in a series of 7 broiler bioassays. The efficiency of energy utilisation of broiler chickens offered sorghum-based diets is problematic and the bulk of dietary energy is derived from sorghum starch. For this reason, rapid visco-analysis (RVA) starch pasting profiles were determined as they may have the potential to assess the quality of sorghum as a feed grain for chicken-meat production. In review, it was found that concentrations of kafirin and total phenolic compounds were negatively correlated with peak and holding RVA viscosities to significant extents across 13 sorghums. In a meta-analysis of 5 broiler bioassays it was found that peak, holding, breakdown and final RVA viscosities were positively correlated with ME:GE ratios and peak and breakdown RVA viscosities with apparent metabolizable energy corrected for nitrogen (AMEn) to significant extents. In a sixth study involving 10 sorghum-based diets peak, holding and breakdown RVA viscosities were positively correlated with ME:GE ratios and AMEn. Therefore, it emerged that RVA starch pasting profiles do hold promise as a relatively rapid means to assess sorghum quality as a feed grain for chicken-meat production. This potential appears to be linked to quantities of kafirin and total phenolic compounds present in sorghum and it would seem that both factors depress RVA starch viscosities in vitro and, in turn, also depress energy utilisation in birds offered sorghum-based diets. Given that other feed grains do not contain kafirin and possess considerably lower concentrations of phenolic compounds, their RVA starch pasting profiles may not be equally indicative.

Performance of broiler chickens offered nutritionally-equivalent diets based on two red grain sorghums with quantified kafirin concentrations as intact pellets or re-ground mash following steam-pelleting at 65 or 97°C conditioning temperatures.

The Liverpool Plains is a fertile agricultural region in New South Wales, Australia. Two sorghums from the 2009 Liverpool Plains harvest, sorghums #3 and #5, were extensively characterised which included concentrations of kafirin and phenolic compounds plus rapid visco-analysis (RVA) starch pasting profiles. Diets based on these two sorghums were formulated to be iso-nitrogenous and iso-energetic and were offered to male Ross 308 broiler chicks from 7 to 28 days post--hatch as either intact pellets or reground mash following steam-pelleting at conditioning temperatures of either 65 or 97°C. Thus the feeding study consisted of a 2 × 2 × 2 factorial array of dietary treatments: two sorghum varieties, two feed forms and two conditioning temperatures. Each of the eight treatments was replicated six times with six birds per replicate cage. Assessed parameters included growth performance, nutrient utilisation, apparent starch and protein (N) digestibility coefficients and disappearance rates from the distal jejunum and distal ileum. Intact pellets supported higher (P < 0.001) feed intakes and weight gains by 9.83 and 9.08%, respectively, than reground mash diets. Feed conversion ratios of broilers offered diets steam-conditioned at 97°C were 2.46% inferior (P < 0.001) in comparison to 65°C diets and both apparent metabolizable energy (AME) and N-corrected AME (AMEn) were compromised. Broilers offered sorghum #3-based diets significantly (P < 0.001) outperformed their sorghum #5 counterparts in terms of weight gain by 3.75% (1,334 versus 1,223 g/bird), FCR by 4.81% (1.524 versus 1.601), AME by 1.06 MJ (13.61 versus 12.55 MJ/kg), ME:GE ratio (ME:GE) by 4.81% (0.806 versus 0.769) and AMEn by 1.03 MJ (12.38 versus 11.35 MJ/kg). The inferiority of sorghum #5 appeared to be associated with higher concentrations of kafirin (61.5 versus 50.7 g/kg) and conjugated phenolic acids, including ferulic acid (31.1 versus 25.6 µg/g). There were no significant differences in jejunal and ileal starch and protein (N) digestibility coefficients between the two sorghums. However, starch to protein (N) disappearance rate ratios from the distal jejunum were significantly (P < 0.001) correlated with ME:GE and AME. The multiple linear regression equations indicated that energy utilisation was enhanced by coupling rapidly digestible protein with slowly digestible starch, which suggests that bilateral bioavailability of starch and protein is pivotal to efficient energy utilisation.

Comparison of tamoxifen with edible seaweed (Eucheuma cottonii L.) extract in suppressing breast tumor.

The tropical edible red seaweed (Eucheuma cottonii L.) is rich in nutrients and polyphenolic compounds that may suppress cancer through its antioxidant and antiproliferative properties. The study reports on rat mammary tumor suppression and tissue antioxidant status modulation by E. cottonii ethanol extract (ECE). The effect of orally administered ECE (100 mg/kg body-weight) was compared with that of tamoxifen (10 mg/kg body-weight). Rat was induced to develop mammary tumor with subcutaneous injection of LA-7 cells (6 × 10(6) cells/rat). The ECE was more effective than tamoxifen in suppressing tumor growth (27%), improving tissues (plasma, liver, and kidney) malondialdehyde concentrations, superoxide dismutase activity and erythrocyte glutathione concentrations (P < 0.05). Unlike tamoxifen, the ECE displayed little toxicity to the liver and kidneys. The ECE exhibited strong anticancer effect with enzyme modulating properties, suggesting its potential as a suppressing agent for mammary gland tumor.

Techniques for analysis of plant phenolic compounds.

Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the presence of total phenolics, while spectrophotometric and chromatographic techniques are utilized to identify and quantify individual phenolic compounds. This review addresses the application of different methodologies utilized in the analysis of phenolic compounds in plant-based products, including recent technical developments in the quantification of phenolics.