Puffed Snacks Research Articles

Effects of processed oats and pinto beans on the composition of human gut microbiome: An in vitro study

Oats and pinto beans, which are rich in dietary fibers and plant proteins, are two common ingredients for many processed food products, such as puffed snacks and canned foods. The objective of this study was to investigate the gut microbiome response to processed oats and pinto beans food products. Raw oats and pinto beans were canned, boiled, and extruded at selected temperatures to simulate the commercial food processing practices. The processed oat and pinto bean samples were digested in an in vitro digestion system, and were subjected to in vitro fermentation by gut bacteria from human feces, which simulated the reactions between the undigested food components and the gut microbiome. The resulting metabolites were quantitatively and qualitatively measured, the compositions of the gut microbiome were determined by 16S rRNA sequencing, and the microbiota were classified and clustered based on their amplicon sequence variants (ASVs) and co-abundancies. The results showed that pinto beans generated more gas and short-chain fatty acids (SCFA) than oats. Boiled oats had a good retention of non-digestible fermentable contents (NDFCs) for the gut microbiota to act on, resulting in greater gas and acid production than other processed oat samples. However, for processed pinto beans, high-temperature extrusion and canning resulted in more NDFCs through starch gelatinization and retrogradation. Guild-based analysis was applied to microbiome analysis to identify key bacteria contributing to microbial shift. Bacteria such as Escherichia-Shigella, Streptococcus, Anaerostipes were promoted in extruded oats, while Lachnospiraceae, Eubacterium hallii, Butyricicoccus were significantly promoted in boiled and low-temperature extruded pinto beans.

Freezing pre-treatment improves radio frequency explosion puffing (RFEP) quality by altering the cellular structure of purple sweet potato [Ipomoea batatas (L) Lam.

Radio frequency explosion puffing (RFEP) is a novel oil-free puffing technique used to produce crispy textured and nutritious puffed snacks. This study aimed to investigate the effects of freezing at different temperatures (−20 °C, −40 °C, −80 °C) for14 h and freezing times (1 and 2 times) on the cellular structure of purple sweet potato and the quality of RFEP chips. The analysis of cell microstructure, conductivity, and rheology revealed that higher freezing temperatures and more freezing times resulted in increased damage to the cellular structure, leading to greater cell membrane permeability and decreased cell wall stiffness. However, excessive damage to cellular structure caused tissue structure to collapse. Compared with the control group (4 °C), the RFEP sample pre-frozen once at −40 °C had a 47.13 % increase in puffing ratio and a 61.93 % increase in crispness, while hardness decreased by 23.44 % (p < 0.05). There was no significant change in anthocyanin retention or color difference. X-ray microtomography demonstrated that the RFEP sample pre-frozen once at −40 °C exhibited a more homogeneous morphology and uniform pore distribution, resulting in the highest overall acceptability. In conclusion, freezing pre-treatment before RFEP can significantly enhance the puffing quality, making this an effective method for preparing oil-free puffing products for fruits and vegetables.

Effects of dietary fibre source and content and extrusion conditions on the physicochemical composition and physical quality of fibre‐enriched lentil snacks

SummaryThe growing recognition of the health benefits associated with dietary fibre and the deficit in its daily intake are propelling the food industry to develop a variety of fibre‐enriched products including puffed snacks. Incorporating rich sources of fibre into pulse‐based foods can supplement the insufficient daily dietary fibre intake. To produce fibre‐enriched puffed pulse snacks and ready‐to‐eat breakfast cereals, three different fibre sources, namely carrot powder (CP), wheat bran (WB) and red lentil hulls (LH), were added to red lentil (RL) flour at 0%, 10% and 20% levels (w/w) and extruded at three extrusion moisture contents (MC), i.e., 18%, 20% and 22% (db). Incorporation of all three fibres into RL flour significantly (P ≤ 0.05) increased the total and insoluble dietary fibre contents and hardness and decreased the expansion index, brightness and crispiness of extrudates. Scanning electron microscopy images revealed that the fibre‐enriched extrudates had thicker cell walls with smaller cells when qualitatively compared to RL extrudates with no fibre addition. CP containing extrudates had significantly (P ≤ 0.05) higher soluble dietary fibre (SDF) content compared to extrudates containing WB and LH. WB containing extrudates were significantly (P ≤ 0.05) harder and less expanded than CP and LH containing extrudates at the same MC. The increase in fibre incorporation level increased the hardness of CP and WB containing extrudates but did not affect LH containing extrudates. Fibre incorporation level also increased the colour differences between RL extrudates with and without fibre enrichment. Increasing MC significantly (P ≤ 0.05) increased the SDF and hardness and decreased the expansion index of extrudates. These results can potentially pave the way for the production of fibre‐enriched pulse‐based puffed products, namely, snacks and ready‐to‐eat breakfast cereals, that are texturally and structurally appealing to consumers.

Evaluation of the Physicochemical, Nutritional, Textural, and Sensory Characteristics of Extrudates From Sorghum and Orange‐Fleshed Sweet Potato Flour Blends

This study is aimed at producing extrudates using sorghum and orange‐fleshed sweet potato (OFSP) flour in varying ratios (90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, and 20:80), with extrudates made from 100% sorghum serving as the control. The puffed snacks’ physicochemical, nutritional, textural, and sensory qualities were assessed, and the obtained data were analyzed through ANOVA. Our findings revealed notable variations in the physicochemical properties of the puffed snacks, showing a decrease in moisture, fat, protein, and crude fibre content as the percentage of OFSP flour increased. Furthermore, increased substitution of sorghum flour with OFSP in the extrudates led to a corresponding rise in vitamin A, B1, and C levels from 0.24, 0.15 and 0.21 mg/100 g in the control to 1.30, 0.19, and 1.82 mg/100 g in the extrudates made from 20% sorghum. More so, samples with increased OFSP content were preferred regarding springiness, chewiness, gumminess, and cohesiveness, whereas those with elevated percentages of sorghum received higher likeness for adhesiveness and stringiness. Extruded samples containing 80% and 90% sorghum levels received the highest overall acceptance ratings of 7.15 and 7.18, respectively. The research results are essential for the food industry to produce nutritious extrudates with appealing sensory characteristics and textures.

Process optimization of wheat flour crisp puffing by radio frequency and the accompanying property changes of starch.

This research performed the process optimization of wheat flour crisp puffing by radio frequency (RF) and investigated the accompanying property changes of starch. Experiments were performed in a 6kW, 27.12MHz pilot-scale RF system. The results showed that the volume expansion was highest (220%) when the conditions were employed as follows: electrode gap (115mm); height of the sample (55mm); initial moisture content of the sample (30%). Under these conditions, the samples were puffed at 120s by RF, and changes in the starch properties were further observed. The results showed that the structure of the starch was destroyed, changing from oval and spherical in shape to fragmented. The crystal type of the starch changed from A to A+V types. Its crystal order was reduced, and the Fourier-infrared spectrum showed that the ratio of (1048/1022)cm-1 decreased from 1.142 to 1.047. The crystallinity decreased from 48.27% to 17.57%. These changes will help starch digestion and absorption in human body. These results indicated that RF puffing could become a potential development method for puffed snacks. PRACTICAL APPLICATION: In this study, the processes of radio frequency puffing wheat flour chips were optimized, and the changes of starch properties during puffing were studied. Therefore, this research provided a theoretical basis for the industrial application of radio frequency puffing.

Effect of rice flour to corn grits ratio and rice bran oil addition on starch digestibility profiles and properties of extruded multigrain puffed snacks

SummaryIngredients play an important role in multigrain puffed snack (PS) quality. Different rice flour (RF) to corn grits (CG) ratios with 3% and 5% rice bran oil (RBO) were assessed for starch digestibility, chemical, and physicochemical properties, and sensory acceptance of PS processed using a twin‐screw extruder. Fat and fibre content significantly increased. PS added with 5% RBO was harder with higher bulk density than 3% RBO. As the CG level increased, the expansion ratio of PS decreased, impacting the physical and sensory properties. The extruded PS exhibited a V‐type crystalline structure originating from the amylose‐lipid complex formation. PS prepared from 50%–60% RF and 10%–20% CG with 5% RBO had the highest content of slow‐digesting starch, resistant starch, antioxidant activity, and total phenolic compounds. The optimal rice flour to corn grits ratio with added RBO of multigrain PS showed potential as a functional snack.

Effects of extrusion cooking on the nutritional quality of puffed snacks made from blends of barley and green lentil flours

Effects of extrusion cooking on the nutritional quality of puffed snacks made from blends of barley and green lentil flours

Lentinus edodes Powder Improves the Quality of Wheat Flour Gluten Sticks.

Spicy wheat flour gluten sticks are delicious and affordable puffed snacks for young adults and even minors in China, and have a relatively simple nutritional quality. L. edodes powder (LEP) is rich in nutrients and boasts a variety of biological activities. This study evaluated the effects of different concentrations of LEP addition on the quality of wheat flour gluten sticks. The gelatinization results of the products showed that the peak viscosity decreased from 454 cP to 251 cP; the breakdown value decreased from 169 cP to 96 cP; and the setback value decreased from 381 cP to 211 cP. With the increase in LEP, the radial expansion rate (RER) of L. edodes gluten sticks (LSGS) first increased and then decreased, reaching a maximum value of 1.388 in the 10% LEP group. The oil absorption rate (OAR) of LSGS increased from 5.124% to 14.852% with the increase in the amount of LEP. Additionally, texture profile analysis showed that the hardness value increased from 1148.898 to 2055.492 g; the chewiness value increased from 1010.393 to 1499.233; and the springiness value decreased from 1.055 to 0.612. Through X-ray diffraction (XRD), it was found that the crystal type was transformed from A-type crystal to B-type and V-type crystals. Low field nuclear magnetic resonance (LF-NMR) results showed that the moisture distribution in the products was basically bound water. The scanning electron microscopy (SEM) results showed that, with the increase in the LEP amount, the surface of the products changed from rough to smooth. Sensory evaluation results indicated that the products with 10% LEP helped to maintain better taste and quality of LSGS, with an average score of 7.628, which was the most popular among consumers. This study not only increases the possible raw materials for use in extruded puffed food, but also provides a new possibility for the production of high-quality edible fungi extruded products.

Processing, characteristics and applications of expanded grains

The popping and puffing are adiabatic expansion process in which the grains are exposed to high temperature for short time. The heat increases vapour pressure inside the grain leading to rupture of outer shell with expansion of starchy endosperm to several folds creating a crispy and aerated puffed snack. Conventional puffing methods use hot air, oil and sand as medium of puffing, whereas non-conventional puffing methods make use of microwave, fluidized air and pressure differential in system. Although it is commonly believed that processing conditions solely influence the quality of expanded grains, many other variables such as physical, chemical and genetic characteristics of grain, post-harvest handling practices, storage conditions and pre-treatments can also largely affect quality indices of expanded grains. As exposed to heat for only short time, expanded grains retain majority of nutrients and even improved digestibility and nutrient bioavailability traits. Flour obtained by milling of expanded grains exhibit desired functional properties expected in bakery products. This paper briefly discussed the factors influencing puffing quality and effects of puffing on physicochemical and morphological characteristics of grain along with its applications.

Fortification of puffed biscuits with chitin and crayfish shell: Effect on physicochemical property and starch digestion.

Chitin is a polysaccharide and possesses numerous beneficial properties such as nontoxicity, biodegradability and biocompatibility, which draws much attention to its applications in food. Crayfish shell is a source of chitin alongside an antioxidants and a potential source of beneficial dietary fiber. In this study, chitin (CH) and crayfish shell (CS) with different concentrations were used to study their impact on pasting characteristics of flour mixture (wheat flour and glutinous rice flour) and influence on physicochemical and starch digestion property of puffed biscuit. The Rapid Visco-Analyzer results showed that the viscosity of powder mixture was decreased with the ratio of CH and CS increased. CH resulted in lowest peak viscosity and breakdown values of mixed powder. It was indicated that increasing amounts of CH and CS led to significantly reduced moisture content, expansion ratio but raised density of biscuits. CH and CS inhibited starch digestion and promoted a remarkable increase (P < 0.05) of resistant starch (RS) content. The hydrolysis kinetic analysis suggested a decelerating influence of CH on the hydrolysis content with lower values of equilibrium hydrolysis percentage (C∞) while CS on hydrolysis rate with lower kinetic constant (K). The estimated glycemic index (eGI) of the CH (15-20%) samples were below 55. These results are of great significance in delaying starch digestion and provided a better choice in design of fried puffed snacks for special crowd with chronic diseases such as diabetes, cardiovascular disease, and obesity.

Delayed Quality Deterioration of Low-Moisture Cereal-Based Snack by Storing in an Active Filler-Embedded LDPE Zipper Bag.

This study focused on controlling the vapor permeability of an active zipper bag and preserving the quality of cereal-based snacks during the storage period at home. The active zipper bag was prepared by extruding low-density polyethylene with active fillers obtained from natural mineral materials. The active zipper bag showed the same transparent appearance as the existing one but showed 21% lower water vapor capability. As a result, during a 20-day storage period, three types of grain-based snacks (biscuits, shortbread cookies, and puffed snacks) showed delayed increases in weight, moisture content, and moisture activity when stored in an active zipper bag. In addition, this also affected the texture of the biscuits and shortbread cookies, in which the area under the curve was reduced significantly after appearing at a peak during the hardness measurement. On the other hand, the decrease in the number of air cell fracture events in puffed snacks was remarkable. This result suggests that the inner microstructure is preserved better when stored in an active zipper bag. In conclusion, the active zipper bag showed poor water vapor permeability, suggesting that the prepared zipper bag can be developed as snack packaging.

Citric acid and sucrose pretreatment improves the crispness of puffed peach chips by regulating cell structure and mechanical properties

Crispness is an important textural attribute of puffed snacks. Impregnation pretreatment is used to regulate the texture of puffed products by changing the cell structure and mechanical properties. In this study, the influence of citric acid and sucrose pretreatment on the cell structure, cell wall components, and mechanical properties of peach slices before puffing drying (heat-pressed slices) was evaluated to understand how citric acid and sucrose pretreatment affects the pore structures and texture characteristics of peach chips with improved crispness. Cell wall degradation, cell structure morphology and mechanical properties before puffing drying interacts to govern the pore morphology and texture characteristics of peach chips. Micrographs of heat-pressed slices showed swollen structures for Cit (citric acid) treated samples and compacted structures for Cit + Suc (citric acid and sucrose) and Cit + Suc + Sdp (citric acid, sucrose and sodium dihydrogen phosphate) treated samples. An increased elastic modulus and decreased viscosity index were observed in all Cit-, Cit + Suc- and Cit + Suc + Sdp-treated samples. After puffing drying, Cit prompted the generation of large pores with low hardness, and Suc and Sdp enhanced the emergence of uniform and small pores with increased hardness. Therefore, crispness was attained by regulating crumbly texture through Cit and regulating hard texture through Suc and Sdp.

X-Ray microtomography imaging of red lentil puffed snacks: Processing conditions, microstructure and texture

Red lentils have a great potential to be used as healthy ingredients in puffed snacks due to their excellent nutritional qualities. However, these types of ingredients with relatively higher protein and fiber content when compared to ingredients that are typically used for the manufacture of puffed foods (e.g., refined cereal flours/starches) result in inferior textural quality. Extrusion processing parameters such as screw speed, moisture content and injection pressure of a blowing agent can be manipulated to optimize the microstructure of an extrudate, and as a consequence the texture of the final puffed product. In this study, X-Ray microtomography imaging is used to characterize and quantify the detailed microstructure of red lentil extrudates. The results indicate that an increase in the injected pressure of the physical blowing agent could be correlated with a decrease in mean cell size and wall thickness, as well as an increase in the number of cells. Evidence of wall rupture with an increased screw speed is also visible, and that effect can be counterbalanced by a higher moisture content during processing. A large variation of the cell wall thickness inside an extrudate (which can induce a weaker cellular structure) as well as a larger cell size and higher amount of wall rupture, significantly reduce the hardness of extrudates. This novel effort to quantitatively characterize the microstructure of red lentil extrudates using X-Ray microtomography establishes that an optimal product texture could, in principle, be achieved by manipulating extrusion parameters to achieve the perfect snack texture.

Effects of particle size and moisture content of maize grits on physical properties of expanded snacks.

The main aim of this research was to investigate the effects of simultaneous changing of maize grits particle size and moisture content on some physical properties and microstructure of the expanded snacks produced by an industrial single screw extruder. Maize grits with different particle sizes of 212-299, 300-474, 475-680, 681-870, 871-1,016, and 1,017-1,070 μm and various moisture contents of 15, 16, 17, and 18% were used to manufacture puffed products. The samples produced with larger particle sizes and higher moisture content exhibited lower water absorption and water solubility indices and less expansion and crispiness than other samples. As microstructure results revealed, these samples showed more uneven surface and thicker cross-section. Overall, controlling both moisture content and particle size of maize grits had significant effects on the quality of the snacks. However, the impact of changing particle size on the snack properties was greater than changing the moisture content. This research has implications in food industry in production of puffed snacks using extrusion process. The results provide practical and green methods of improving the quality of the snacks by choosing the appropriate feed particle size and moisture content. The approach introduced in this paper is easy to impediment in the food industry without the need to change extruder configuration or adding to the list of ingredients and additives.

Bean-based nutrient-enriched puffed snacks: Formulation design, functional evaluation, and optimization.

School‐age children frequently consume snacks. However, most of the snacks they consume are of low nutritional quality. The objective of this study was to develop a nutrient‐rich and acceptable extruded bean‐based snack, which could contribute to improved nutrient intake, especially for school‐age children. Snack formulations developed from Roba1 beans, maize, orange‐fleshed sweet potato, and amaranth mixtures, and processed in a twin‐screw extruder, were evaluated and optimized for nutritional, textural and sensory properties. High proportion of beans in the formulation was associated with high protein, iron, zinc, and dietary fiber content. An optimal formulation (82.03:10: 5:2.97; beans, maize, OFSP, amaranth), containing 20.38 g, 4.12 g, 4.83 mg, and 1.51 mg per 100 g, of protein, dietary fiber, iron, and zinc, respectively, was obtained. The snacks were crunchy and moderately acceptable with average sensory scores of 6 on a 9‐point hedonic scale, and hardness 26.6 N. Nutrient contribution 43, 19, and 12% for protein, iron, and zinc, respectively, to children aged 6 to 8 years; and 24, 19, and 7.6%, respectively, to children aged 9 to 12 years from a 40 g serving was estimated from the snack. The results demonstrate the potential of using extrusion to produce nutrient enriched value‐added food products from blends of iron‐rich beans and common staples.

Development of a Model System for Tasting Grain Varieties.

This study investigated suitable approaches and effective applications for the evaluation of grain flavor differences among cultivars. A model system that helps to facilitate the characterization of flavors in grain varieties was developed using sorghum grain as a tool. Five different applications were initially used, including cooked grain, porridge, cookies, muffins, and extruded puffed snacks. Six highly trained sensory panelists participated in the project. The effectiveness of each application was determined based on the results of the attribute generation process and from panelist feedback. The results indicate that the combination of a cooked whole grain procedure and the use of flour made into cookies provides an effective and potent model for flavor characterization in both their grain form and as finished products. Both the recipes for the cooked grain and cookie applications effectively brought out the flavor characteristics of the grains as well as differentiated the flavor differences between grain cultivars. The developed model can be applied for the flavor evaluation of multiple grain types and can help researchers understand the flavor differences among grain cultivars. As a result, such knowledge will help to facilitate the selection of suitable products with favorable characteristics for specific applications as well as for selective breeding purposes.

Effects of extrusion conditions and nitrogen injection on physical, mechanical, and microstructural properties of red lentil puffed snacks

PurposeRed lentils are rich in proteins and fibres, and thus have great potential to be used as healthy ingredients in extruded snacks. However, at high protein and fibre concentrations, the level of expansion, microstructure uniformity and textural appeal are impaired. Using physical blowing agents during extrusion can overcome these quality issues. This study investigates the effects of moisture content (18%–22%), screw speed (150 rpm–200 rpm), and blowing agent (i.e., N2) injection pressure (0−500 kPa) on physical, mechanical and microstructural properties of puffed red lentil snacks. Principle resultsCompared to conventional extrusion, N2 injection at 300 kPa decreased extrudate density from 0.25 to 0.41 kg/m3 to 0.12 to 0.26 kg/m3 (across all feed moistures and screw speeds studied), and substantially altered the extrudate’s microstructure. Extrudates with N2 injection had numerous small cells that were more evenly distributed. Moreover, an increase in feed moisture from 18% to 22% increased extrudate hardness and decreased crispiness. Major conclusionsN2 injection during extrusion has a great potential in manipulating extrudate expansion, microstructure, texture, and colour of red lentil extrudates. Extrudates produced with 300 kPa N2 injection pressure had the maximum expansion compared to other N2 injection pressures studied.

Optimization and characteristics of extruded puffed snacks with Agaricus bisporus powder and rice flour

AbstractUsing rice flour and Agaricus bisporus powder as raw materials, a puffed snack was developed by twin‐screw extrusion technology. The Box–Behnken design method was used to optimize the process variables with three factors in three levels. The experimental variables were included temperature (135°C–155°C), moisture (13%–17%) and the addition amount of A. bisporus powder (3%–7%). The extrudate properties were evaluated by determining the expansion ratio. The optimization results indicated that the extrusion temperature was adjusted to 149°C, the moisture content of raw materials was 14.4%, and the addition of A. bisporus powder was 4.2%. Under these conditions, the expansion rate of the product was up to 3.41. The obtained extruded snacks had good taste, high expansion ratio and loose porosity. Compared with snacks without A. bisporus powder, the puffed snacks had better characteristics (high consumer tasting score, relatively low hardness).Practical applicationsAfter making the puffed snacks, fruits and vegetables were easy to store and transport and enrich the products of A. bisporus. The puffing rate, consumer evaluation and hardness of A. bisporus snacks were studied, which provided a theoretical basis for optimizing the processing characteristics of A. bisporus. Agaricus bisporus and rice flour provided great space for the development of puffed food.

Extrusion cooking of gluten‐free whole grain flour blends

AbstractWhole grain flour blends from maize, rice, and sorghum were processed in a single screw extruder to produce puffed snacks and the physical properties of the extrudates were determined. Blends from sorghum or maize at high proportions (70%) produced extrudates with low expansion, high apparent density, and small and uniformly distributed air bubbles in their structures that affected texture. Suspensions rich in sorghum reduced setback viscosities. Extrudates produced from equal proportion of maize, rice, and sorghum presented low compression forces and minimum crispness work, whereas blends with high proportion of sorghum affected these textural responses negatively. The choice of a blend of equal proportion of whole grain flours of those three components would allow to produce nutritious puffed snacks with relatively higher dietary fiber content, provided by maize and sorghum, higher protein content by sorghum component, and higher crispness by rice.Practical applicationsThe use whole grains is growing in gluten‐free products, due to the benefits of its components (dietary fiber, phytochemicals, protein, vitamins, and minerals) which make them attractive raw materials for designing new alternative foods with health benefits. Gluten‐free cereals: maize, rice, and sorghum are available sources in the Americas, particularly in Brazil and in the United States. The thermoplastic extrusion is a cooking technique that allows the combination of heat and shear causing unique changes to the textural properties of the final product. Therefore, whole grain flours with appropriate modulation of the extrusion parameters can be used to create fiber rich cereal products.The use of gluten‐free whole grain flours blends includes ready‐to‐eat dietary fiber rich snacks (puffed extrudates) and, with appropriate milling, it could also be used as ingredient for baking applications, dehydrated instant foods (porridge), cereal beverages, as well as for other innovative applications in the food industry.

Physical and functional properties of wheat flour extrudates produced by nitrogen injection assisted extrusion cooking

Extrusion cooking is widely used to produce cereal-based puffed snacks and food ingredients with superior functionality. The effects of nitrogen injection with three pressure levels (0, 100 and 200 kPa) on physical and functional properties of wheat flour extrudates were investigated in this study. The performance of nitrogen gas as a physical blowing agent and the effect of nitrogen injection pressure as a new extrusion cooking parameter were also evaluated. Nitrogen injection significantly decreased extrudate density and increased extrudate's expansion index. Nitrogen assisted extrudates had less yellow, less red but brighter color, increased crunchiness, and cold viscosity. Extrudate's water solubility increased significantly at 200 kPa nitrogen injection pressure, but no effect on water binding capacity was observed. The use of nitrogen as a physical blowing agent substantially affected all physical properties studied. The manipulation of nitrogen injection pressure as a new extrusion parameter also showed noticeable effects on water solubility and pasting properties of extrudates. Nitrogen injection during extrusion can potentially be used to produce a wider range of aerated snack foods. The manipulation of nitrogen injection pressure could be a new approach to produce more functionalized food ingredients fit for different end-products.