Response surface methodology for evaluation and optimization of process parameter and antioxidant capacity of rice flour modified by enzymatic extrusion

Optimization of process parameters for the development of gluten free extruded breakfast cereal based on Quinoa, finger millet and red rice using RSM

Current research aims to evaluate the effect of high shear extrusion on quinoa, finger millet, and red rice composite flour-based breakfast cereal using response surface methodology with extruder barrel temperature (120-130 °C), screw speed (320-350 rpm) and feed moisture content (10-20 g/100 g) as independent variables. Product responses were fitted on to mathematical model using second-order polynomial equations. Multiple regression analysis of data revealed the high statistical significance of respective mathematical models. Numeric optimization based on acceptable product characteristics revealed optimized processing conditions (barrel temperature 130 °C, screw speed 350 RPM, and feed moisture content 20 g/100 g) with a desirability of 0.9373. Extrudates developed using selected processing conditions along with optimized ones and control were characterized for their nutrient profile and crystallinity. Breakfast cereal developed using optimized processing conditions showed a better nutritional profile and reduction in crystallinity of product after high shear extrusion processing represented starch gelatinization.

Assessment of physicochemical, rheological, and thermal properties of Indian rice cultivars: Implications on the extrusion characteristics

The implications of physicochemical, rheological, and thermal properties of seven eminent Indian rice cultivars (PR 114, 121, 122, 123, 124, 126, and 127) on the extrusion behavior and physico-functionalities of the extrudates were investigated. The amylose and amylopectin content of the cultivars ranged between 12.72 to 28.86% and 71.14 to 87.28% in addition with protein and crude fat content that varied from 7.05 to 9.15% and 0.49 to 1.17%, respectively. The onset (r = 0.98), peak (r = 0.95), and conclusion (r = 0.98) temperatures of the cultivars were in positive correlation with amylose. Likewise, pasting temperature (r = 0.979), final viscosity (r = 0.91), set back viscosity (r = 0.89), and stability ratio (r = 0.90) of the cultivars demonstrated a significant positive correlation with the amylose content. However, peak (r = - 0.879) and hold viscosity (r = - 0.89) were negatively correlated. The cultivars were extruded at feed moisture of 15%, screw speed of 500 rpm and barrel temperature of 150°C. The extrudates characteristics viz., expansion ratio-1.82 (PR 123); bulk density-184 g/cc (PR 123); specific mechanical energy-262.35 Wh/kg; water absorption index (WAI)-6.26 (PR 122); water solubility index-48.52% (PR 123); hardness-148.63 N (PR 122); and hydration power-284% (PR 122) were viably hyphenated with the physicochemical and rheological behavior of cultivars. The physico-functional characterization of the extrudates in terms of their starch and protein structural indexes, α-amylase susceptibility; water soluble carbohydrates and proteins revealed the possibility of exploring these cultivars as a functionally viable and diverse ingredient for the production of ready-to-eat extrudates.

Development of a Novel Rice-Based Snack Enriched with Chicory Root: Physicochemical and Sensory Properties

A novel rice-based snack enriched with chicory root flour (CRF) was developed by twin-screw extrusion. Chicory (Cichorium intybus L.) is one of the promising medicinal plants for the development of innovative food and may be considered a functional food ingredient. Central composite design (CCD) was employed to generate snack formulations by varying feed moisture (M, 16.3–22.5%), screw speed (SS, 500–900 rpm) and CRF content (20–40%). The optimization according to artificial neural network modeling and a genetic algorithm was applied to define optimal process conditions (17.6% moisture, 820 rpm and 24.1% of CRF) for obtaining the product with the highest expansion (3.34), crispiness (3.22 × 10−3), volume (2040 m3), degree of gelatinization (69.70%) and good color properties. Bulk density (110.33 g/L), density (250 kg/m3), and hardness (98.74 N) resulted in low values for the optimal sample. The descriptive sensory analysis evaluated low hardness and bitterness, with high crispiness for the optimal extrudate. This study points to the possibility of a novel chicory enriched extrudate production with desirable physicochemical and sensory properties.

Feasibility of Extruded Brewer’s Spent Grain as a Food Ingredient for a Healthy, Safe, and Sustainable Human Diet

This study aimed to determine the effect of the extrusion process on the nutritional and bioactive profiles of brewer’s spent grain (BSG), contributing to nutrition security by applying a circular economy concept. Response surface methodology was used to optimize the effect extrusion parameters (moisture content, screw speed, and barrel temperature ) had on BSG’s soluble dietary fiber, free glucose, and overall antioxidant capacity. Proximate composition analyses, amino acid profile, extractable polyphenolic content, and antioxidant capacity of BSG and brewer’s spent grain extruded under optimal conditions (BSGE) were carried out. Food safety was analyzed by their microbiological quality, gluten, and acrylamide content. Optimal extrusion conditions were 15.8% of moisture content, 164.3 revolutions per min and 122.5 °C. BSGE presented 61% more soluble dietary fiber than BSG, lower digestible starch, 0.546% of free glucose, and protein quality parameters mostly like those reported for egg, soy, and milk. Despite this, BSG’s overall antioxidant capacity was not improved after thermomechanical processing; BSGE had significantly higher extractable polyphenolic content in its alkali extracts, which were determined qualitatively by high-performance liquid chromatography quadrupole time-of-flight assay in its hydro-alcoholic acid extracts. Furthermore, although it is not gluten free, BSGE is a safe food ingredient with acceptable microbiological quality and no acrylamide.

Effect of extrusion technology on hempseed (Cannabis sativa L.) oil cake: Polyphenol profile and biological activities

Effects of extrusion with varying barrel temperature, moisture content, and screw speed on hempseed oil cake were studied for the first time. Extrusion at lower moisture (30%) and higher screw speed (300 rpm) significantly increased the proportion of free polyphenols, flavonoids, and phenylpropionamide content, and α -glucosidase and acetylcholinesterase inhibition activities. Full factorial design confirmed the three-way interactions among all extrusion parameters for all chemical assays with the bound phenolic fraction, total flavonoid content, and DPPH inhibition activity of the free phenolic fraction. HPLC-DAD-ESI-QTOF-MS/MS analysis tentatively identified 26 phenylpropionamides, and the contents of N-trans-caffeoyltyramine (66.26 µg/g) and total phenylpropionamides (85.77 µg/g) were significantly increased after extrusion at the lower moisture and higher screw speed extrusion conditions. The higher α -glucosidase inhibition activity at higher screw speed could be due to the N-trans-caffeoyltyramine (r = 0.99, p < 0.01), while the AChE inhibition activity appeared to be influenced more by the cannabisins A-C, M (r > 0.8, p < 0.01). PRACTICAL APPLICATION: Hempseed oil cake is a byproduct of oil extraction, with high protein and high fiber contents. The results of this research could be used directly in food industry to improve the nutritional and commercial value of hempseed oil cake by extrusion technology.

Optimization of the Drum Drying Parameters and Citric Acid Level to Produce Purple Sweet Potato (Ipomoea batatas L.) Powder Using Response Surface Methodology

Purple sweet potato (PSP) is a rich source of anthocyanins, but the anthocyanin content and color can be affected by the drying method and processing condition. Response surface methodology (RSM) with a Box-Behnken design (BBD) was used to investigate the effects of citric acid (CA) concentration, steam pressure (SP) and rotation speed (DS) on the physicochemical and functional properties of drum-dried purple sweet potato powder (PSPP). The anthocyanins of the PSPP were analyzed using mass spectrometry with electrospray ionization and twelve anthocyanins were identified. The results indicated that the moisture content (4.80 ± 0.17-9.97 ± 0.03%) and water activity (0.290 ± 0.004-0.47 ± 0.001) (p < 0.05) decreased with increasing drum temperature as well as with reduced drum rotating speed. CA had a significant (p < 0.05) effect on the color and total anthocyanin content (101.83 ± 2.20-124.09 ± 2.89 mg/100 g) of the PSPP. High SP and low DS negatively affected the antioxidant properties of the PSPP. DPPH value of the PSPP ranged from 20.41 ± 0.79 to 30.79 ± 1.00 μmol TE/g. The optimal parameters were achieved at 0.59% CA, 499.8 kPa SP and 3 rpm DS.

A comprehensive review of cereal germ and its lipids: Chemical composition, multi-objective process and functional application

Cereal germ (CG), a by-product of grain milling, has drawn much attention in the food industry because of its nutritional and functional advantages. Nowadays, the utilization of cereal germ from animal feeds to foodstuff is a popular trend. CGs have high content of polyunsaturated fatty acids in their lipids (43.9-64.9% of total fatty acids), but they are also induced to oxidative rancidity under the catalytic reaction of enzymes. Chemical and structural properties of lipids in CGs are affected by different treatments. Thermal and non-thermal effects prevent lipid oxidation or promote lipid combination with starch/protein in CG. Thus, the functional properties and final quality of CG are directly changed. In this review, the chemical composition and application of CGs especially the endogenous lipids are summarized and the effects of various processes on CG lipids/matrices are discussed for CG future development.

Considerations for improvising fortified extruded rice products

Micronutrient fortification of rice by extrusion is an effective strategy to enhance micronutrient levels within rice-consuming individuals. The success of extrusion-based fortification is associated with micronutrient retention, enhanced bioavailability, low postprocessing losses, prolonged storage stability, and minimal sensory changes. The success of an optimally fortified product is primarily reliant upon the compositional considerations, but many attributes of extrudates can be indebted to the processing parameters too. Hence, an exhaustive investigation of this technology has been taken-up here, emphasizing on the compositional parameters in association with process parameters, which influence the final quality attributes like nutrient stability, bioavailability, and sensory properties. Based on these attributes of the end product, a collected data have been presented here to bring out the optimal compositional requirements. These together with cooking processes, extrusion process parameters, and storage conditions will enable formulate a product with enhanced sensory acceptance, better retention during cooking and storage, improved texture, and acceptable color. This review will thus help to optimize a need-based product, its quality, and enhance benefits of fortified extruded rice products.

Extrusion improves the phenolic profile and biological activities of hempseed (Cannabis sativa L.) hull

The impact of extrusion at different barrel temperature and screw speed on the hempseed hull was investigated. The extrusion treatments showed significant (p < 0.05) increase in total phenolic content, proportion of free phenolic compounds, and DPPH and ABTS radical scavenging activities. At low screw speed (150 rpm), significantly (p < 0.05) higher α-glucosidase and acetylcholinesterase inhibition activities were observed in the extruded samples. The full factorial model revealed a significant interaction between extrusion parameters on total phenolic/flavonoid content and antioxidant activities for free fraction, and α-glucosidase and acetylcholinesterase inhibition for whole fraction. A total of 26 phenylpropionamides, including hydroxycinnamic acid amides and lignanamides, were identified by HPLC-ESI-QTOF-MS/MS. HPLC-DAD analysis showed a 25-78% increase in total phenylpropionamide content in hempseed hull after extrusion. Pearson's correlation displayed significant (p < 0.05) positive correlation of N-trans-caffeoyltyramine, the most abundant phenylpropionamide, with all biological activities (r = 0.832-0.940).

Response Surface Methodology for Optimization of Process Parameters and Antioxidant Properties of Mulberry (Morus alba L.) Leaves by Extrusion

Mulberry (Morus alba L.) leaves (MLs), originally used to feed silkworms, have recently been recognized as a food ingredient containing health-beneficial, bioactive compounds. In this study, the extrusion process was applied for the enhancement of the amount of extractable flavonoids from MLs. Extrusion conditions were optimized by water solubility index, total phenolic content, and total flavonoid content (TF) using response surface methodology, and antioxidative stress activities were evaluated in macrophage cells. According to the significance of regression coefficients of TF, the optimal extrusion parameters were set as barrel temperature of 114 °C, moisture feed content of 20%, and screw speed of 232 rpm. Under these conditions, the TF of extruded ML reached to 0.91% and improved by 63% compared with raw ML. Fifteen flavonoids were analyzed using ultra-high-performance liquid chromatograph coupled with photodiode array detection and quadrupole time-of-flight mass spectrometry (UPLC-PDA-QTOF/MS), and the extrusion resulted in increases in quercetin-3-gentiobioside, quercetin-3,7-di-O-glucoside, kaempferol-3,7-di-O-glucoside, rutin, isoquercitrin, and moragrol C. Besides, regarding antioxidative activity, extruded ML water extract inhibited the production of H₂O₂-induced reactive oxygen species and attenuated nuclear morphology alterations in macrophage cells. The findings of this study should be useful in food processing design to improve the extractable functional compounds in MLs.

Production of innovative gluten-free breakfast cereals based on red and black rice by extrusion processing technology

The transformation of black and red, broken or not, whole rice grains, into breakfast cereals is an interesting way to add value to these snacks for some reasons. Firstly, broken kernels hardly achieve a high market value; whole rice is healthy not only for their nutrient contents but also for their phytochemical profile, rich in phenolic compounds; breakfast cereals from pigmented rice are colored by themselves, and any additional colorant is unneeded; finally, rice is naturally gluten-free and suitable for those with conditions like celiac disease or gluten sensitivity. The objective of this study was to optimize some extrusion parameters that account for the physicochemical properties of extrudates by using response surface methodology. Feed moisture between 15 and 21% and the 4th barrel zone temperature between 110 and 160 °C were the independent variables. Specific features such as color, texture, water solubility and absorption, cold viscosity, expansion, specific volume, and compression force were evaluated. The trials have shown that moisture had a higher impact on the extrusion process than temperature. Less expanded, denser, harder, and darker products were obtained at higher moisture levels. The optimum points were defined at 15.5% and 16.0% of feed moisture and 159 °C and 150 °C of temperature for black and red rice extrudates, respectively. These conditions resulted in cereal breakfast balls with optimal water solubility, volume, texture, and good color. Additionally, cold viscosities and a low compression led to products with a potential high approval by consumers.

Effect of exogenous metal ions and mechanical stress on rice processed in thermal-solid enzymatic reaction system related to further alcoholic fermentation efficiency

Metal-rich thermal-solid enzymatic processing of rice combined with yeast fermentation was investigated. 8 Metal ions were exogenously supplied at 0.05, 0.5 and 5mmol/100g (MG) rice prior to static high pressure enzymatic cooking (HPEC) and dynamic enzymatic extrusion cooking (EEC). Treated rice and its fermentation efficiency (FE) were characterized by rapid viscosity analyzer (RVA), UV-Vis, FT-IR and atomic absorption spectrophotometer (AAS). The optimum pH range of enzyme in solid system (>4.9) was broader than in a liquid system (>5.5). Cations decreased enzymatic activity in HPEC probably due to metal-induced aggregation of rice matrix with reduced reacting area as well as strengthened structure of starch/polysaccharides modified by metals. While using the EEC with mechanical mixing/shearing, relative activity was activated to 110 and 120% by Mg²⁺ (0.05-0.5MG) and Ca²⁺ (0.05-5MG), respectively. Furthermore, the effectiveness of residual ions to promote further FE was found to follow the order: Ca²⁺>K⁺>Zn²⁺>Mg²⁺>Mn²⁺>Na⁺≈Control>Fe²⁺>Cu²⁺, individually.