Effect of Extrusion on Physicochemical Properties, Digestibility, and Phenolic Profiles of Grit Fractions Obtained from Dry Milling of Normal and Waxy Corn

Development, Characterization and Sensory Evaluation of an Extruded Snack Using Fig Molasses By-Product and Corn Semolina

The effects of extrusion process parameters on the physicochemical, pasting and technological properties of ready-to-eat snacks were evaluated. The aim was to develop fortified extruded products with fig molasses by-product powder (FMP), which is created as a result of the production of fig molasses, is not currently used in food industry, and may cause environmental problems. The feed humidity was changed to 14-17-20%, the die temperature was 140-160-180 °C and the ratio of FMP was 0-7-14% at a fixed screw speed of 325 rpm. The study showed that adding FMP to extruded products had a significant effect on colour properties, water solubility and water absorption index properties. İncreasing the FMP ratio had a significant reducing effect on dough properties of non-extruded mixtures such as peak viscosity (PV), final viscosity (FV) and setback viscosity (SB). The optimum conditions for the production of snacks were found to be 7% FMP, 155.44 °C die temperature and 14.69% humidity. It was determined that the estimated values of water absorption index (WAI) and water solubility index (WSI) for the products manufactured under ideal extrusion conditions were close to the obtained values, and that there was no significant difference between the estimated values of the other response variables and their actual values.

The effect of Vaccinium bracteatum Thunb. leaves addition on antioxidant capacity, physicochemical properties, and in vitro digestibility of rice extrudates

Vaccinium bracteatum Thunb.leaves (VBTL) are a traditional Chinese herbal medicine with potential natural pigments and antioxidants. Its application information on extrusion is limited. In this study, to increase the usage of foods containing VBTL, rice-based extrudates with VBTL were investigated. The extrusion was performed at a wide temperature range (60-140°C) and with different VBTL supplementations (3%-10%). The extrudates with 10% VBTL showed a significant decrease in total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity upon extrusion. TPC and TFC increased with the rise of barrel temperature. The VBTL color was stable during the wide-temperature extrusion process. The bioactivities of the extrudates were positively correlated with the VBTLsupplement (R = 0.943-0.989). In addition, different addition levels of VBTL significantly changed the water absorption index (WAI), water solubility index (WSI), pasting properties, and in vitro starch digestibility of the extrudates. Moreover, extrudates with 3% VBTL showed the highest WAI and peak viscosity but the lowest in vitro starch digestibility. These results may suggest that rice extrudates with a low supplement of VBTL have an acceptable color and may be used as functional additives for high antioxidant and low glycemic response diets. PRACTICAL APPLICATION: The results showed that the Vaccinium bracteatum Thunb. leaves (VBTL) color and antioxidation were stable during the wide-temperature extrusion process. Extrusion processing can be used to enlarge the usage of VBTL and simplify its traditional processing method. Applying VBTL to the process of extrusion appears to be a suitable method of producing value-added and low glycemic response extrudates.

Changes in Phenolics during Cooking Extrusion: A Review

In this paper, significant attention is paid to the retention of phenolics in extrudates and their health effects. Due to the large number of recent articles devoted to total phenolic content (TPC) of input mixtures and extrudates, the technological changes are only presented for basic raw materials and the originating extrudates, and only the composites identified has having the highest amounts of TPC are referred to. The paper is also devoted to the changes in individual phenolics during extrusion (phenolic acids, flavonoids, flavonols, proanthocyanidins, flavanones, flavones, isoflavons, and 3-deoxyanthocyanidins). These changes are related to the choice or raw materials, the configuration of the extruder, and the setting the technological parameters. The results found in this study, presented in the form of tables, also indicate whether a single-screw or twin-screw extruder was used for the experiments. To design an extrusion process, other physico-chemical changes in the input material must also be taken into account, such as gelatinization of starch; denaturation of protein and formation of starch, lipids, and protein complexes; formation of soluble dietary fiber; destruction of antinutritional factors and contaminating microorganisms; and lipid oxidation reduction. The chemical changes also include starch depolymerization, the Maillard reaction, and decomposition of vitamins.

Diversity and relationship among grain, flour and starch characteristics of Indian Himalayan colored corn accessions

The present study examined the diversification and relationship among grain, flour and starch characteristics of thirty eight differently coloured corn accessions. The differences among accessions were more pronounced due to heterogeneity in genetic traits than color. Colour properties were positively related with phenolics and antioxidant activity. K, Ca, Zn, Mg, Na, Cu, Fe and Mn were the prominent minerals present in accessions. Accumulation of 10 polypeptides, ranging from 10 to 95 kDa was also evaluated. HPLC analysis showed the presence of gallic acid, Catechin, caeffic acid, chlorogenic acid, protocatechuic acid, p-coumaric acid, vanillic acid, quercetin, sinapic acid, ferulic acid, reservatrol and luteolin in flours. Accessions had higher proportions of amino acids, citrulline, arginine, GABA, phenylalanine, isoleucine, tyrosine, threonine, glycine. Starch granules with different particle size showed angular structure. Final viscosity, set back viscosity and crystallinity positively related to amylose content of starch. Starches with A-type crystalline pattern showed variability in thermal properties. The results of this study showed significant relationship between DPPH and total phenolic content, thermal properties, amylose content and crystallinity among various corn germplasm. These will be helpful for selection of appropriate accessions having required characteristics not only for food applications but also for non-food ones.

Physical and technofunctional properties of yellow pea flour and bread crumb mixtures processed with low moisture extrusion cooking

The potential utilization of yellow pea flour and bread crumb blends was investigated to generate nutritionally-dense extruded products with superior physical and/or technofunctional properties. Yellow pea flour mixed with bread crumb at different ratios were processed using low-moisture twin-screw extrusion cooking conditions to examine the effect of blending ratios and feed moisture contents on physical (that is, radial expansion index, extrudate density, microstructure, texture, and color) and technofunctional (that is, emulsifying capacity, emulsifying stability, water solubility [WS], water binding capacity [WBC], oil binding capacity [OBC], and pasting) properties of the final products. Compared to the two feed materials alone, samples produced with yellow pea flour and bread crumb blends showed lower hardness and higher crispiness. Moisture content (12% to 18%) was found to significantly affect physical and technofunctional properties. With an increase in feed moisture content from 12% to 18%, the WBC of the extrudates increased while the WS decreased. Extrudates produced with higher feed moisture content, and higher yellow pea flour content had higher setback viscosity. Among all formulas and feed moisture contents studied, extrudates produced with 50% yellow pea flour and 50% bread crumb at 12% feed moisture content had the highest radial expansion and bigger cells with thinner cell walls. This study has shown that incorporation of yellow pea flour and bread crumb in extrusion cooking process could be used to develop nutritionally-dense foods with improved physical and technofunctional properties.

Quality and estimated glycemic profile of baked protein-enriched corn chips

This study aimed to develop gluten-free protein-enriched corn snack chips and evaluate their physical properties and in vitro estimated glycemic index. Flours containing yellow corn and soybean flours, and soy protein isolate (in a proportion of 2.5:1.0:1.0 by weight respectively), cellulose gum, salt, and baking powder were homogeneously mixed followed by the addition of water and kneaded to form a dough. Response surface methodology was used to optimize baking powder levels (0-2.0%), dough sheet thickness (0.7-1.7 mm), and baking time (6-12 min) of the chips baked at 160 °C. Dough sheet thickness and baking time had significant effect on all the examined physical properties (water activity ranged from 0.15 to 0.71, hardness ranged from 377 to 2105 g, and browning index ranged from 38.4 to 60.7) (P < 0.05) except fracturability. However, all the variables had a significant quadratic effect on the fracturability (ranged from 1 to 23 peaks) of the chips (P < 0.01). The chips prepared from 1.2% baking powder, 1.2 mm dough sheet thickness, and baked for 9.0 min were considered the best and were significantly lower in the estimated GI value (48.8) (P < 0.05) when compared to non-soy corn chips (75.0). These baked protein-enriched corn chips developed could be considered as protein-rich and low glycemic index healthy snacks.

Evaluation of phenolic antioxidant-linked in vitro bioactivity of Peruvian corn (Zea mays L.) diversity targeting for potential management of hyperglycemia and obesity

Peruvian corn biodiversity is one of the highest in the world and may represent an important natural source of health relevant phenolic bioactive compounds whose potential needs to be investigated. This study investigated twenty-two Peruvian corn samples corresponding to five corn races (Arequipeño, Cabanita, Kculli, Granada and Coruca) in relation to their total phenolic contents (TPC), anthocyanin contents, Ultra-Performance Liquid Chromatography (UPLC) phenolic profiles and antioxidant capacity (ABTS and ORAC methods). Subsequently using both free and cell-wall bound phenolic fractions their health relevance targeting hyperglycemia (α-glucosidase and α-amylase inhibition) and obesity (lipase inhibition) potentials was evaluated using in vitro assay models. Antioxidant capacity and TPC were high in bound fractions from yellow-colored races in contrast to the purple-colored race (Kculli) which had high TPC (mainly anthocyanins) and antioxidant capacity in the free form. The major phenolic acids detected by UPLC were ferulic and p-coumaric acids. High α-glucosidase (32.5-76.1%, 25 mg sample dose) and moderate α-amylase inhibitory activities (13.6-29.0%, 250 mg sample dose) were found in all free fractions, but only samples from the Kculli race had lipase inhibitory activity (58.45-92.16%, 12.5 mg sample dose). Principal component analysis revealed that the variability of data was affected by the race and the α-glucosidase and lipase inhibitory activities positively correlated with anthocyanins and antioxidant capacity. Some accessions of Kculli, Granada and Cabanita races are promising for future breeding strategies focused on the development of improved corn varieties targeted for the design of functional foods relevant for hyperglycemia and obesity prevention.

Effect of chickpea and spinach on extrusion behavior of corn grit

The present work was carried out to see the effect of blending of corn grit (CG) with varying levels of chickpea grit (CP 0-100%) and spinach leaf powder (SP 0-6%) on the characteristics [color, expansion, density, hardness, water absorption index, total phenolic content (TPC), antioxidant activity (AOA; as DPPH and ABTS free radical scavenging activities)] and sensory properties of extrudates. CP and SP were rich in proteins and minerals (Cu, Fe, Zn, Mg, Ca, K and Na). Their blending significantly influenced the physicochemical and antioxidant properties of CG extrudates. TPC and AOA of extrudates increased with the increased incorporation of CP and SP, though specific mechanical energy and extrudate expansion, generally, decreased while density and hardness increased. Sensory analysis revealed that CP and SP at incorporation levels of 25% and 4%, respectively could be blended with CG for making highly acceptable antioxidant-rich expanded snack.

Physicochemical evaluation of corn extrudates containing varying buckwheat flour levels prepared at various extrusion temperatures

This study analyzed the characteristics (physicochemical properties as well as antioxidant activity) of corn grit extrudates containing buckwheat flour at various levels (0, 10, 20 and 30% w/w) extruded at various temperatures (130, 150 and 170 °C). Effect of roasting (92 °C for 15 min) on the extrudates was also studied. Buckwheat incorporation at different levels mainly increased the diameter, a* value (indicating redness), phenolic content and antioxidant capacity, while decreased bulk density and water absorption index of the extruded products. On the other hand, increment in extrusion temperature primarily increased the L* values (lightness), a* values and antioxidant activity but decreased the phenolic content of extrudates. Roasting improved the flavor and texture of the extrudates which was desirable. Extrudates prepared from corn grit with incorporation of buckwheat up to 20% level and extrusion cooking at 150 °C showed best sensory scores.

Optimization of process parameters for the development of finger millet based multigrain extruded snack food fortified with banana powder using RSM

Extrusion cooking is a high temperature short time process where food materials are cooked in a barrel with a combination of pressure, moisture and temperature. In this study a finger millet based snack product fortified with banana powder is extruded with a combination of rice flour, corn flour and cheese and its properties are studied. In addition to that the parameter for extrusion cooking of the snack product is also optimized. Response surface methodology was used to optimize the process parameters like barrel temperature (118-122 °C), extruder rpm (345-355) and banana powder concentration (1-4 g) on physical and functional properties of extruded snack food based on finger millet. Central composite design with three levels, three factors is used for optimization. Analysis of variance was used to study the effects of process parameters. Regression analysis is also done for variability and it is fitted to a second order quadratic model with coded value for each response. Based on Analysis of Variance model confirmed the fitness for dependent variables.

Value additon of kinnow industry byproducts for the preparation of fiber enriched extruded products

In the present study dietary fiber enriched vermicelli from wheat flour supplemented with debittered kinnow industry by-products (pulp residue and pomace) has been developed. Functional, cooking and textural properties of both supplemented and unsupplemented vermicelli were evaluated. Vermicelli containing 15% debittered kinnow pulp residue and pomace showed minimum cooking loss (18.5, 20.0%) but higher swelling index (2.06, 1.87), water absorption capacity (153, 202 g/100 g) and optimal cooking time (9.34, 9.02 min). Firmness and fracturability of vermicelli supplemented debittered pulp residue (10.0 and 21.5) and pomace (16.7 and 16.1) was higher as compared to control sample (6.1 and 2.1) respectively. Further, redness, firmness, TPC, DPPH activity and water absorption capacity of vermicelli got increased with addition of debittered kinnow pulp and pomace. The utilization of debittered kinnow pulp and pomace in vermicelli can provide dual benefit like production of healthy food products along with solving the problem of solid waste disposal of kinnow industry byproducts.

In vitro digestion of meat- and cereal-based food matrix enriched with grape extracts: How are polyphenol composition, bioaccessibility and antioxidant activity affected?

The aim of this study was to evaluate the effect of enriching a complex food matrix (FM) with grape extracts on polyphenol content, composition, bioaccessibility and antioxidant activity during digestion. The grape extracts and FM were separately tested under the same conditions as controls. The FM by itself contains a significant amount of phenolic acids and flavonols, influencing the final recovery of polyphenols from grape extracts. The FM significantly increased the total recovery of polyphenols after digestion of grape seed extracts compared to those digested without the FM; however, a low recovery of proantocyanidins and total flavonoids was observed. Digestive fluids and FM compounds significantly increased the total polyphenol content of grape digests and significantly contributed to their ABTS⁺ scavenging activity and ferrous-ion-chelating capacity. The present study suggested that enrichment of meat- and cereal-based products with grape polyphenol extracts could be a good strategy to formulate a healthier diet.

Cereal by-products as an important functional ingredient: effect of processing

Cereal is a staple food and major nutrition source throughout the world. The cereal bran obtained from milling as by-product contains multiple benefits and health-promoting components such as dietary fiber, minerals, vitamins, polyphenols, and phytosterols. However, these by-products are usually undervalued and used in animal feed. To increase the functional and food value, processing techniques linked to improving nutritional characteristics, sensory properties and reducing the inhibitory factors have been developed. These processing techniques include mechanical, enzymatic and thermal processing. It aims to improve the functional properties, enhance the extractability of beneficial food ingredients, reduce the complex structure of the bran and improve solubility, decrease the content of inhibitory factors and improve the bio-accessibility of micronutrients. This review highlights the various technological interventions and application of appropriate processing techniques to process cereal bran for the isolation of functional food ingredient and thus utilizing the nutritious by-product of cereal processing industry.

Evaluation of quality changes in nutritionally enriched extruded snacks during storage

The aim of this study was to evaluate changes in the physical, chemical and sensory properties of a low fat-high protein, fiber enriched extruded snack. It was packed in metalized polypropylene/polyethylene (PP/PE) laminate pouches, under modified atmosphere packaging (MAP) with nitrogen flushing and without nitrogen flushing (control) and stored for a period of 22 weeks at 37 ± 1 °C and 80% RH. MAP had significant impact on the moisture content, aw, TBA value, Hunter L* value and crispiness of the extruded snacks during storage. The moisture content of the snack significantly increased from 3.68 to 5.16% in control and from 3.66 to 4.31% in MAP. The oxidative rancidity in terms of TBA value of control sample increased from 0.02 to 0.07 while the product packaged under MAP, the value increased to 0.056. The sensory scores for flavour, color and appearance, texture and overall acceptability (OA) of the product significantly decreased during storage, but the product stored under MAP had better flavor (6.51) and OA scores (6.85) compared to control (5.58 and 6.04, respectively), after 22 weeks of storage. Thus, MAP tended to retard the storage induced changes and it could suitably be utilized for the delivery of low fat-high protein, fiber enriched extruded snacks to the consumer, while keeping the sensorial acceptance of the product for 5 months.

Effect of feed components on quality parameters of wheat-tef-sesame-tomato based extruded products

Wheat flour is one of the principal ingredients in extruded wheat products. Wheat-based extruded products have relatively low protein and high gluten contents as well as a high glycemic index. Incorporation of nutrient-rich supplements could overcome those limitations. A D-optimal statistical experimental design was used to develop high-value and nutrient-rich extruded products by supplementing wheat flour (WF), with tef flour (TF), sesame protein concentrate (SPC) and tomato powder (TM). Effects of feed compositions on physical and functional properties of the extruded products were evaluated and modeled using an artificial neural network (ANN). SPC contributed to elevate the protein and simultaneously lower the carbohydrate content of the extruded products while TF and TM contributed to improving crude fiber and antioxidant properties. Evaluated physicochemical properties were adequately predicted by the ANN models (R2 = 0.979-0.998) with root mean square error of less than 0.008. Physical properties and sensorial evaluation correlated well and revealed that TF, SPC and TP addition to wheat flour produced distinct extruded products rich in protein and antioxidants with lowered carbohydrate and gluten contents.

Influence of process parameters on physical properties and specific mechanical energy of healthy mushroom-rice snacks and optimization of extrusion process parameters using response surface methodology

Ready-to-eat healthy mushroom-rice snacks were developed and processed using twin-screw extruder. A 15% of oyster mushroom power could be added to improve the nutritional values of the rice based snack. The effects of process parameters (feed moisture, screw speed and barrel temperature) on physical properties and Specific Mechanical Energy (SME) during the production were investigated. Feed moisture was varied at 12-18% wet basis and the screw speed was studied in the range of 275-425 rpm, while the barrel temperature was operated at 130-150 °C. The result indicated that bulk density differed significantly with changes in all the process parameters. An increasing barrel temperature caused higher expansion ratio, while hardness of snacks increased due to an increase of feed moisture and a decrease of screw speed. SME was considered by measuring the electric current and voltage of the extruder. As a result, feed moisture demonstrated the most influence on the SME. Feed moisture between 12 and 15% wet basis, the SME decreased with decrease in feed moisture. On the other hand, the SME decreased when the higher feed moisture was operated in the range of 15-18% wet basis. In addition, the process condition was optimized using response surface methodology. From this study, the optimum extrusion-cooking conditions with respect to the physical qualities of snacks and SME during extrusion was 13.5% of feed moisture, screw speed of 425 rpm and maximum barrel temperature at 130 °C, since these conditions provided a good quality mushroom-rice snacks and consumed low SME.

Influence of blue maize flour on gluten-free pasta quality and antioxidant retention characteristics

Due to its bioactive compounds, blue maize flour is a valuable ingredient for developing gluten-free products. The incorporation of alternative flours into gluten-free pasta is a challenge as it usually results in products that, despite their enhanced nutraceutical features, show reduced quality characteristics. Composite pasta was prepared with variable (25, 50 and 75%) contents of flours from white and blue maize, chickpea and unripe plantain, following a laboratory-scale process. The composite pasta exhibited acceptable cooking loss (9-11%); pasta with blue maize showed lower hardness and chewiness, but higher adhesiveness than its white maize-based counterpart. Blue maize-based pasta presented dark color. The addition of blue maize flour at 75% conveyed the highest total phenolic content retention after extrusion (80%) and cooking (70%). Pasting profile of blue maize pasta (50 and 75%) showed a defined second viscosity peak due to re-arrangement of starch components upon cooling. The observed retention of phenolic compounds with antioxidant capacity after cooking will be useful for further development (selection of ingredients, formulations and conditions of operation) of gluten-free products with potential health benefits.

Effect of pregelatination on rheology, cooking and antioxidant activity of pasta

The present study explores the possibility of using twin screw extruder for preparation of pregelatinized pasta. The effects of extrusion parameters feed moisture (28 and 32%), barrel temperature (60-105 °C) and screw speed (100-200 rpm) on pregelatinized pasta were investigated. Prepared pasta was analysed for quality characteristics in terms of cooking quality, degree of gelatinization, color, texture, pasting properties, bioactive composition. Results indicated that higher screw speed improved the cooking quality of pasta and decreased gruel solid loss. Degree of gelatinization revealed positive relation with temperature and feed moisture. Extrusion conditions, altered the color of pasta, a decrease in L*, increase in a* and b* values was observed. Higher peak viscosity was observed at lower barrel temperature and feed moisture. A significant retention in total phenolic content and flavonoid content was observed with higher feed moisture. Extrusion leads to increase in antioxidant activity and firmness upon increasing screw speed and feed moisture.

Enrichment of rice-based extrudates with Cactus Opuntia dillenii seed powder: a novel source of fiber and antioxidants

The present study investigated the effects of adding the powder of cactus Opuntia dillenii (O. dillenii) seeds on the functional properties, fiber, antioxidants and acceptability of rice-based extrudates. The control blend consisting basically of rice flour was replaced with O. dillenii seed powder at 2, 4, 6, 8, 10, 15 and 20% then extruded at the optimum processing conditions. The extruded products were evaluated for their chemical composition, functional properties, color attributes, antioxidant activity and sensory characteristics. The results revealed that adding O. dillenii seeds powder enhanced the fiber, phenolics, flavonoid contents and antioxidant activity of extrudates. Expansion, bulk density and breaking strength were significantly decreased, while water absorption index, water solubility index and oil absorption index were significantly increased compared to the control. Furthermore, the mean scores of sensory evaluation indicated clear improvements in all tested sensory attributes, which significantly increased by increasing the level of O. dillenii seed powder up to 15%. The results confirmed that O. dillenii seed powder could be incorporated in rice to develop snack products of acceptable functional, nutritional and sensory properties.

Bioactive compounds and antioxidant activities of some cereal milling by-products

The present study was performed to evaluate the phytochemicals profiles of some cereal milling by-products such as wheat (bran, germ and shorts), rice (bran, germ and husk) and corn (bran, germ and germ meal) to assess their potentiality as bioactive compounds sources. Distilled water, ethanol, methanol, and acetone separately were used as solvents for the extraction of phytochemicals compounds. The antioxidant activity (AOA), total phenolics content (TPC), and total flavonoids content (TFC) of the extracts were investigated using various in vitro assays. The results showed that tannins content was ranged from 113.4 to 389.5 (mg/100 g sample).The study revealed that TPC and TFC of cereal by-products extracts were significantly different for various solvents. TPC content varied from 366.1 to 1924.9 mg/100 g and TFC content varied from 139.3 to 681.6 mg/100 g. High carotenoids content was observed for corn germ meal and minimum for wheat bran. Distilled water, ethanol and methanol extracts showed significantly different antioxidant activity. Significant variations were observed with regard to AOA of different cereal by-products by using various solvents. The ethanol and methanol were observed to be the best solvents to extract phenolic compounds and antioxidant activity, while acetone extract showed less efficiency. Also, the cereal milling by-products were rich in bioactive compounds and could be used as a value added products.

Changes in functional properties and in vitro bioaccessibilities of β-carotene and lutein after extrusion processing

In this research, carrot pulp was added to traditional snack made from corn-grit. As the biological activity of carotenoids in the body depends on their bioaccessibility, change in carotenoid bioaccessibility during extrusion processing was investigated. In addition, phenolic content, antioxidant activity, β-carotene and lutein contents were investigated before and after the extrusion process. Two different temperature profiles were used for extrusion process. In-vitro bioaccessibilities of β-carotene and lutein increased by extrusion, β-carotene at both temperature profiles while lutein only at higher temperature profile. Extrusion decreased the antioxidant activity, total phenolic, β-carotene and lutein contents. Results suggest that even though amount of functional components decrease, in vitro bioaccessibility could be enhanced by extrusion. Therefore, carrot pulp can successfully be added as a functional ingredient to extrudated.

Effect of processing on phenolic acids composition and radical scavenging capacity of barley pasta

Phenolic acids, total phenolics content and DPPH radical scavenging capacity in raw ingredients, fresh and dried spaghetti, and in uncooked and cooked spaghetti were evaluated and compared with semolina spaghetti as a reference. Ferulic acid was the major phenolic acid found in the free and bound phenolic extracts in all the investigated pasta samples. The addition of barley flour into pasta at incorporation levels of 30, 50 and 100% increased phenolic acids and total phenolics content. Pasta processing did not significantly affect the total phenolics content and free radical scavenging capacity, but a significant reduction in total phenolic acids measured by HPLC was found. Drying process differently affected individual phenolic compounds in the free and bound fractions, and thus, the total phenolic acids content. Free vanillic, caffeic and p-coumaric acids did not significantly change, while p-hydroxybenzoic and ferulic acids of the free extracts showed higher values compared to the corresponding fresh pasta. Cooking did not greatly affect total phenolic acids, more leading to conserving free and bound phenolic compounds.

Characteristics of normal and waxy corn: physicochemical, protein secondary structure, dough rheology and chapatti making properties

The physicochemical, protein secondary structure, dough rheological and chapatti making properties of normal and waxy corn types were evaluated. Waxy corn grains showed the highest L* and b* value, while red-pigmented corn grains had the highest a* value. Higher accumulation of K, Mg, Na and Ca minerals in corn was recorded, while Cu, Mn, Fe and Zn were present in trace. Meal prepared from waxy corn had higher L*, a* and b* values as well as ash, protein and fat content. A significant decrease in various mixograph parameters was observed with increase in water level during dough development. A decrease in dynamic rheological parameters (G', G'' and tan δ) of dough from all corn types was recorded with increase in water level. Dough developed from waxy corn meal had lower G' and G'' as compared to that from normal corn types. FTIR spectra of dough from different corn types at different water levels showed various peaks in amide-I region with most prominent peak at about 1650 cm-1 followed by 1640-1645 and 1610-1620 cm-1 regions. The peak intensities increased with increase in water level which was an indicative of the increase in intermolecular and antiparallel (IM + AP) β-sheet as well as α-helix and β-sheet structures. Dough developed from waxy corn showed change in peak intensities at high moisture level only. The chapatti made from normal (yellow) corn showed higher consumers' acceptability score, while that from waxy corn was poor.

Application of Moldavian dragonhead (Dracocephalum moldavica L.) leaves addition as a functional component of nutritionally valuable corn snacks

Application of Moldavian dragonhead (Dracocephalum moldavica L.) leaves in extruded snacks was evaluated. Directly expanded corn snacks (crisps) were supplemented with 5-20% of dragonhead leaves. The supplemented snacks were characterized to have improved nutritional value and were a good source of dietary fibre. The presence of phenolic compounds, especially rosmarinic acid, showed a high antioxidant potential and a radical scavenging activity of tested snacks, especially if a high content of additive was used. The increasing amount of additive also had an impact on the physical properties of extrudates lowering the expansion ratio, water absorption and solubility, yet increasing bulk density, cutting force and the breaking index of the enriched snacks. The highest viscosity was observed at 5 and 10% addition level. The increasing amount of dragonhead leaves lowered the brightness of snacks and increased the greenness tint significantly. A sensory evaluation showed good acceptability of snacks enriched with up to 15% of dragonhead dried leaves. Dried leaves of the Moldavian dragonhead seem to be a prospective functional additive for extruded crisps with a high nutritional value, especially because of dietary fibre and rosmarinic acid content, a strong antioxidant potential and acceptable sensory properties.