Understanding the Effect of Single- and Twin-Screw Extrusion Processing Parameters on Physical and Physico-Chemical Properties of Sprouted Quinoa and Sprouted Proso Millets

According to Mordor Intelligence Research, the new compositional research and moisture content extrusion process are helping the growth of the plant protein market. The demand for plant proteins is growing at a fast rate, owing to change in lifestyle, lack of balanced dietary intake, and improved research and development in order to develop new kinds of plant-protein enriched products. It is necessary to identify the right plant protein sources and choose the right processing methodology to create highly digestible foods which can be consumed by infants and elderly as well. In addition, it is important to support local farmers and help them make value added products. The primary objective of this study was to investigate the feasibility of developing extruded foods from protein rich sprouted quinoa and proso millet flours with high protein and starch digestibility. The secondary objective was to understand the effect of extrusion processing conditions on the systems parameters and on the physical and physico-chemical properties of the extruded product. Quinoa and Proso millet were chosen as the grains of interest due to their high protein content as compared to wheat, rice, corn, amaranth and buckwheat. The study was broadly then divided in to three parts. In the first part, pre-treatment methods such as soaking and sprouting were analysed for effective reduction of saponins and phytic acid and increased starch and protein digestibility. The sprouting of quinoa increased the starch digestibility from 55.6% on Day 0 to 78.2% on Day 4. A similar increase in the protein digestibility was observed from Day 0 (42.2%) to Day 4 (75.5%). Sprouting also produced similar effects in proso millet where the starch digestibility increased from 51.7% (Day 0) to 77.1%. The breakdown of the phytates during sprouting of proso millet increased the protein digestibility from 46.4% on Day 0 to 76.8% on Day 4. Simultaneously the reduction of saponin content in quinoa and phytic acid content in both grains were observed. The saponin content in raw quinoa of 0.8g/100g was reduced to 0.1g/100g samples (Day 4) by germination. The phytic acid content in quinoa reduced from 1.1g/100g to 0.1g/100g (Day 4) and in proso millet reduced from 1.5g/100g to 0.2g/100g (Day 4). The color of the flour produced from the sprouted grains were significantly different from the unprocessed flour respectively. The L* value of sprouted quinoa flour was darker (L*=61.2) as compared to the control sample (L* = 82.6). Similarly, the sprouted proso millet flour was darker (L*=70.1) than the unprocessed proso millet flour (L*=84.2). In the second part, the extrusion process of sprouted quinoa was divided into three experiments. The first experiment is the single screw extrusion of sprouted quinoa. Using a response surface design to understand the influence of feed moisture content (15-25% w.b), die temperature (80-140°C), screw speed (90-220 rpm) and germination time (Days 0-4) on the physical and physico-chemical properties of sprouted quinoa extrudates was studied. The following responses were obtained: bulk density (116-154 kg/m3), hardness (1.05-1.8 N), water solubility index (11.5-16.5%), water absorption index (2.36-3.51), total color difference ΔE (14.8-21.7), expansion ratio (2.52-3.75), protein digestibility (80.5-86.5%) and starch digestibility (80.1-85.8%). The die temperature and germination time played a significant role in product responses. The second experiment was designed to create a puffed product with an inclusion of corn meal. Corn meal is the most common ingredient of expanded snacks in the food market. Because of its composition, ratio of vitreous to floury endosperm, and particle size, under optimal extruding conditions corn meal makes for a light, highly expanded, crunchy and soft product. Single-screw extrusion processing of sprouted quinoa-corn meal blend was studied using a response surface design to understand the influence of feed moisture content (15-25% w.b), die temperature (80-140°C), screw speed (90-220 rpm), corn meal ratio (0-30%) and quinoa time (Days 0-4) on the physical and physico-chemical properties of sprouted quinoa- corn meal blend extrudates. The following responses of the extrudates were measured and the values ranged from: bulk density (102-145 kg/m3), hardness (1.03-1.62 N), water solubility index (12.3-19.9%), water absorption index (2.44-3.79), total color difference ΔE (14.1-21.4), expansion ratio (2.75-3.97), protein digestibility (78.4-85.8%) and starch digestibility (77.5-85.6%). The addition of corn meal improved the color difference and expansion ratio of the extrudates. The third experiment employed a twin-screw extruder to understand the influence of feed moisture content (15-25% w.b), die temperature (80-140°C), screw speed (90-220 rpm) and germination time (Days 0-4) on the physical and physico-chemical properties of sprouted quinoa flour extrudates. The bulk density (132-175 kg/m3), hardness (1.56-2.14 N), water solubility index (14.4-18.5%), water absorption index (2.93-3.41), ΔE (16.7- 20.8), expansion ratio (2.28-2.83), protein digestibility (78.4-84.1%) and starch digestibility (77.1-83.4%) were measured. All independent parameters had statistically significant effects on all the extrudate characteristics. Twin screw extrusion did not improve the extrudate characteristics significantly. Poor expansion ratio was observed as compared to single-screw extrusion. Similar experiments were carried out for sprouted proso millet flour. Single-screw extrusion processing of sprouted proso millet flour was studied using a Box Behnken response surface design to understand the influence of feed moisture content (15-25% w.b), die temperature (80-140°C), screw speed (90-220 rpm) and germination time (Days 0-4) on the physical and physico-chemical properties of proso millet extrudates. The following responses of the extrudates were measured and the values ranged from: bulk density (101-137 kg/m3), hardness (1.01-1.3N), water solubility index (14.8-18.7%), water absorption index (4.0-4.41), ΔE (13.0-17.1), expansion ratio (3.28-3.75), protein digestibility (78.2-86.6%) and starch digestibility (80.9-87.7%). Both feed moisture content and extruder die temperature had statistically significant effects on all the extrudate characteristics. Extruder screw speed had minimal effect on the extrudate properties. It was followed by a single-screw extrusion processing of sprouted proso millet-corn meal blend with feed moisture content (15-25% w.b.), die temperature (80-140°C), screw speed (90-220 rpm), corn meal ratio (0-30%) and proso millet germination time (Days 0- 4) on the physical and physico-chemical properties of sprouted proso millet-corn meal blend extrudates. The following responses of the extrudates were measured and the values ranged from: bulk density (100-143 kg/m3), hardness (0.84-1.59 N), water solubility index (12.5-20.1%), water absorption index (2.55-3.90), total color difference ΔE (13.07-20.37), expansion ratio (2.74-3.96), protein digestibility (78.5-85.9%) and starch digestibility (77.7-85.8%). The addition of 30% corn meal significantly increased the expansion ratio from 3.29-3.96. Last study was to investigate the effects of twin-screw extrusion processing of sprouted proso millet with feed moisture content (15-25% w.b), die temperature (80-140°C), screw speed (90-220 rpm) and germination time (Days 0-4) on the physical and physicochemical properties of sprouted proso millet extrudates. The responses from the experiment include: bulk density (132-175 kg/m3), hardness (1.56-2.14 N), water solubility index (14.4-18.5%), water absorption index (2.93-3.41), ΔE (16.7-20.8), expansion ratio (2.28-2.83), protein digestibility (78.4-84.1%) and starch digestibility (77.1-83.4%). The expansion ratio was significantly poor when compared to the single screw extrusion of sprouted proso millet. In the third and last part, a comparative study on the efficacy of Response Surface Methodology (RSM) and Artificial Neural Network (ANN) in modelling of single and twin-screw extrusions were conducted. We optimized the neural network topology to predict the error and regression coefficient and root mean square error using artificial neural network and compared the results with response surface methodology for single screw (sprouted quinoa, sprouted quinoa-corn meal blend, sprouted proso millet, sprouted proso millet-corn meal blend) and twin screw (sprouted quinoa and sprouted proso millet) extrusion processes. Irrespective of the ingredient composition and blend for all extrusion processes, ANN predictions have regression coefficients greater than 0.9 and RSM predictions are greater than 0.8. Similarly, the root mean square error values were low in all ANN predictions are compared to RSM. Based on error analysis results, the prediction capability of ANN model is found to be the best of all the prediction models investigated, irrespective of food composition and extrusion processes

Scientific Insights and Technological Advances in Gluten Free Products Development

This Special Issue addresses both new scientific insights and technological advances of gluten-free product development exploring alternative ingredients for the development of gluten-free products aiming to mimic the unique viscoelastic properties of gluten as a gas retention ingredient during fermentation, water binding and enabler of starch gelatinization on baking, and a bread flavor enhancer via gluten-related proteases

Optimisation of co-culture fermentation of lactobacillus casei and propionibacterium jensenii in rice bran extract

Co-culture fermentation is a fermentation process involving two defined microorganisms growing together in the same culture. A co-culture of lactic acid-producing bacteria (LAB) and propionic acid-producing bacteria (PAB) is beneficial in producing direct-fed microbial (DFM) products. The synergistic activity between LAB and PAB in co-culture fermentation can improve the survival of LAB and the growth of PAB. On this basis, the objectives of this study are two-fold. Firstly, the optimisation of co-culture fermentation involving Lactobacillus casei and Propionibacterium jensenii in the agricultural waste extract. Secondly, the development of an artificial neural network (ANN) predictive model for predicting the cell biomass concentration and the co-culture-specific growth rate. In the preliminary phase, two different substrates, namely rice bran and banana peel, were used in this study. This step was conducted to select the suitable carbon source for L. casei to grow and produce lactic acid for P. jensenii consumption. From the observation, rice bran was found more suitable as a carbon source and fermentation medium. Next, the co-culture optimisation of L. casei and P. jensenii fermentation was conducted using the one-factor-at-a-time approach. The fermentations were optimised for rice bran at concentration of 5% to 25% w/v; incubation temperature (30? to 42?); inoculation ratio (1:1 to 1:10 % v/v) and the initial pH (5.0 to 7.0). The optimum fermentation condition was obtained at 20% w/v rice bran concentration, incubated at 35? with an inoculation ratio of 1:4 % v/v and initial pH of 6.5. The optimum growth (2.74 g dry cell weight/L) was recorded after 96 hours of incubation. The highest viable cell counts for L. casei and P. jensenii were 9.10 log CFU/mL and 9.42 log CFU/mL, respectively. The optimum specific growth rate, µ obtained, was 0.41 h-1. The growth of L. casei and P. jensenii was compared to its monoculture fermentation, and it was found that the co-culture did not affect the growth of L. casei but helped maintain its survival. Moreover, P. jensenii gained benefits in the co-culture system, as its growth improved compared to during its monoculture. The ANN predictive model was developed using the multilayer perceptron and trained using the Levenberg-Marquardt training algorithm. Five input parameters, incubation time (h), the concentration of total reducing sugar (g/L), pH culture, incubation temperature (?) and inoculation ratio (% v/v), were used to train the network for the prediction of cell biomass concentration (g/L) and the co-culture specific growth rate, µ (h-1). The model has a low mean square error and high regression coefficient (R2) for the training and testing set, indicating the model is fit to predict the cell biomass produced and its specific growth rate during the co-culture of L. casei and P. jensenii. The structure obtained for ANN predictive model consist of five inputs, eight hidden nodes and two outputs, 5-8-2. The optimum predicted cell biomass concentration and the specific growth rate, µ, were 2.24 g dry cell weight/L and 0.51 h-1, respectively. In conclusion, this work provides a strategy to produce multispecies DFM through co-culture fermentation using rice bran and presented the first predictive ANN model to predict the cell biomass concentration and the co-culture-specific growth rate of L. casei and P. jensenii

Fermentation in the gut to prolong satiety : exploring mechanisms by which dietary fibres affect satiety in pigs

Obesity has become a major health problem in humans and companion animals. Although obesity is not common in farm animals, food restriction is often used to maintain low feeding costs and performance of, for instance, pregnant sows and fattening pigs. Food restriction may result in hunger and increased feeding motivation, which are associated with behavioural problems. Knowledge on the regulation of satiety is thus crucial to aid in the control of food intake in humans, and to improve welfare in food-restricted farm animals. Dietary fibres are believed to enhance satiety, but the effectiveness varies with the physicochemical properties of the fibre sources concerned. Therefore, the objective of this thesis was to identify whether and how dietary fibres with different physicochemical properties, such as bulkiness, viscosity, gelling and fermentability, affect satiety in the domestic pig, which was used both as a model for humans and as a target animal. In a study focusing on behavioural measures of satiety, pectin (viscous fibre) was the least satiating, whereas lignocellulose (bulking fibre) and resistant starch (fermentable fibre) were the most satiating fibres tested. In a subsequent study, increasing levels of guar gum, inulin, and resistant starch (all fermentable fibres), when replacing digestible starch, enhanced satiety throughout the day. Resistant starch was the most satiating fibre among all fibres tested, and used, in a subsequent study, to assess possible physiological and molecular mechanisms by which fermentation may affect satiety. Also in this study, resistant starch appeared to enhance satiety based on behavioural observations, i.e. reduced feeder-directed and drinking behaviours during 24 h. As expected, the satiating effects of resistant starch coincided with increased 24 h plasma short-chain fatty acids (SCFA) levels and decreased postprandial glucose and insulin plasma levels. Glucagon-like peptide-1 (GLP-1) plasma levels were lower in pigs fed resistant starch, whereas peptide tyrosine tyrosine (PYY) plasma levels were not affected by resistant starch, suggesting that these hormones do not play a role in the increased satiety induced by fermentation. Resistant starch consumption led to downregulation of genes involved in immune responses, and upregulation of genes involved in metabolic processes such as fatty acid and energy metabolism in the proximal colon. Moreover, correlation analysis inversely linked potential pathogenic microbial groups with plasma SCFA concentrations and with genes involved in fatty acid metabolism. These findings suggest that besides satiating effects, resistant starch has a beneficial effect on colonic health. In the last study, the long-term effects of a gelling fibre promoting satiation (alginate) and a fermentable fibre promoting satiety (resistant starch) on feeding patterns and growth performance were assessed. In the long-term, growing-finishing pigs compensated for a reduced dietary energy content by increasing voluntary food intake (alginate), or they became more efficient in the use of digestible energy (resistant starch). Moreover, dietary fibres increased the relative weight of the gastrointestinal tract and led to changes in body composition (less fat more muscle), which may be relevant for the maintenance of lean weight in humans. In conclusion, fermentable fibres are more satiating than viscous and bulking fibres. The satiating effects of fermentable fibres are likely mediated by an increased SCFA production, and a reduced and attenuated glucose supply. Under unrestricted feeding conditions, dietary fibres promoting satiation (alginate) and satiety (resistant starch) did not reduce long-term food intake and total body weight gain, yet, colon empty weight was increased and carcass growth was reduced. This implies that changes in body composition and intestinal weight or content, rather than body weight and body mass index (BMI) alone may be relevant to fully acknowledge the effects of fibres to aid in maintaining or promoting healthy body weight in humans.</p

Scientific, Health and Social Aspects of the Food Industry

This book presents the wisdom, knowledge and expertise of the food industry that ensures the supply of food to maintain the health, comfort, and wellbeing of humankind. The global food industry has the largest market: the world population of seven billion people. The book pioneers life-saving innovations and assists in the fight against world hunger and food shortages that threaten human essentials such as water and energy supply. Floods, droughts, fires, storms, climate change, global warming and greenhouse gas emissions can be devastating, altering the environment and, ultimately, the production of foods. Experts from industry and academia, as well as food producers, designers of food processing equipment, and corrosion practitioners have written special chapters for this rich compendium based on their encyclopedic knowledge and practical experience. This is a multi-authored book. The writers, who come from diverse areas of food science and technology, enrich this volume by presenting different approaches and orientations

Recent Advances on The Enhanced Thermal Conductivity of Graphene Nanoplatelets Composites: A Short Review

Graphene nanoplatelets (GNPs) have attracted significant attention in the field of thermal management materials due to their unique morphology and remarkable thermal conductive properties. In addition, their impressive thermal properties make them interesting nanofillers for producing multifunctional composite materials with a multitude range of applications. This work specifically reviews the recent advances of the application of GNPs as nanofillers for the development of enhanced thermal conductivity of various materials or composites. In this review, the insight on the improved thermal conductivity of the composites bestowed by the GNPs with comprehensive comparison are briefly discussed. This review might unlock windows of opportunities and paves the way towards the production of enhanced materials for thermal applications including electronics, aerospace devices, batteries, and structural reinforcement

Pathways to Water Sector Decarbonization, Carbon Capture and Utilization

The water sector is in the middle of a paradigm shift from focusing on treatment and meeting discharge permit limits to integrated operation that also enables a circular water economy via water reuse, resource recovery, and system level planning and operation. While the sector has gone through different stages of such revolution, from improving energy efficiency to recovering renewable energy and resources, when it comes to the next step of achieving carbon neutrality or negative emission, it falls behind other infrastructure sectors such as energy and transportation. The water sector carries tremendous potential to decarbonize, from technological advancements, to operational optimization, to policy and behavioural changes. This book aims to fill an important gap for different stakeholders to gain knowledge and skills in this area and equip the water community to further decarbonize the industry and build a carbon-free society and economy. The book goes beyond technology overviews, rather it aims to provide a system level blueprint for decarbonization. It can be a reference book and textbook for graduate students, researchers, practitioners, consultants and policy makers, and it will provide practical guidance for stakeholders to analyse and implement decarbonization measures in their professions

Pathways to Water Sector Decarbonization, Carbon Capture and Utilization

The water sector is in the middle of a paradigm shift from focusing on treatment and meeting discharge permit limits to integrated operation that also enables a circular water economy via water reuse, resource recovery, and system level planning and operation. While the sector has gone through different stages of such revolution, from improving energy efficiency to recovering renewable energy and resources, when it comes to the next step of achieving carbon neutrality or negative emission, it falls behind other infrastructure sectors such as energy and transportation. The water sector carries tremendous potential to decarbonize, from technological advancements, to operational optimization, to policy and behavioural changes. This book aims to fill an important gap for different stakeholders to gain knowledge and skills in this area and equip the water community to further decarbonize the industry and build a carbon-free society and economy. The book goes beyond technology overviews, rather it aims to provide a system level blueprint for decarbonization. It can be a reference book and textbook for graduate students, researchers, practitioners, consultants and policy makers, and it will provide practical guidance for stakeholders to analyse and implement decarbonization measures in their professions