Quality and storage stability of extruded puffed corn-fish snacks during 6-month storage at ambient temperature

BACKGROUND: Cereal‐based snacks are usually low in protein and other nutrients. Increased health awareness of consumers has led the food industry to develop fortified snacks with functional ingredients. Three types of extruded corn‐fish snacks, containing 150 g kg^?1 carp mince and 150 g kg^?1 trout mince, 30 g kg^?1 freeze‐dried saithe protein and a regular corn snack (control). were produced to study quality changes and storage stability of the products during 6‐month storage at 27 ± 2 °C. RESULTS: All products had the same level of water activity and proximate composition except for protein. Fortified snacks had a protein content of 93–98 g kg^?1, compared with 65 g kg^?1 in the control. A significant increase was observed for peroxide value during storage (0.0 to 2.8 meq kg^?1). Scores for attributes describing oxidation and off odors and flavors increased after 5–6 months' storage but attributes describing puffed corn snack odor and flavor did not change during storage of any of the products. CONCLUSION: Extrusion of corn grits with fish flesh/fish protein can be used to produce high‐protein products that would be an option to provide nutrient snacks for consumers and to increase fish consumption. Copyright © 2011 Society of Chemical Industry     

FRACTURE BEHAVIOR AND MECHANISM OF PUFFED CEREAL DURING COMPRESSION

Texture of puffed cereals was determined to develop an instrumental method and to provide a mechanism of compaction under compressive stress. A model solidlike puffed rice at different moisture contents (2.0–8.5%) was subjected to compression testing to determine the fracture/failure characteristics. The force–deformation curves showed three zones and two firmnesses during compression. The different textural parameters were sensitive to moisture content above 6%. The microstructure of puffed rice consisted of many closed air cells having thin cell walls (10–15  µ m) while a compressed sample showed breaking of cell walls with simultaneous development of fracture lines. A mechanism of compaction or failure at macromolecular level for puffed rice has been proposed based on texture data and microstructure.

PRACTICAL APPLICATION

The acceptance of a snack food largely depends on the texture which in turn is related to fracture characteristics. The present paper offers a general method for determining the texture of snacks and similar brittle food products. The developed indices can describe the texture of a snack food. The mechanism of failure, developed in the present work, can also be applied for low-density foods and for prediction of their behavior during compression.     

Extruded puffed functional ingredient with oat bran and soy flour

Extrusion cooking is a food processing technique that is used worldwide to transform various ingredients. The aim of this work was to apply extrusion to develop a functional puffed ingredient with defatted soy flour and oat bran and the minimum amount of corn starch required to attain good textural properties. The proportions of the feed ingredients and the processing conditions (extruder temperature, moisture, and inulin percentage as a technological coadjutant) were optimized. Applying mixture experimental design to study the effect of feed ingredients on expansion and textural properties of extruded product, the formula containing 250 g/kg corn starch, 375 g/kg soy flour, and 375 g/kg oat bran was selected as the best between tested. Using this blend and applying incomplete factorial design, the best process conditions (250 g/kg moisture; 45 g/kg inulin and 130 °C) were chosen. Based on the results of the process, optimization step temperatures higher than 130 °C were tested and showed that 160 °C increased the radial expansion ratio and decreased hardness the most. The obtained puffed product had 212.6 g/kg fiber, 281.0 g/kg protein, and a caloric value of 319.1 kcal/100 g. It was well accepted by the panelists in the sensory evaluation, mainly in terms of texture.     

Development of ready‐to‐eat rice starch‐based puffed products by coupling freeze‐drying and microwave

The rice starch mixtures with varying amylose contents (AC) of 0.12–19.00% weight were prepared by mixing waxy and nonwaxy rice starches. The 5% rice bran oil shortening was added in the starch paste. After gelatinisation, thin slabs of starch pastes were aged at 4 °C for 24 h. The aged slabs were dried by freeze‐drying to obtain 25% moisture content. A microwave oven set to 600 J s^?1 for 90 s was then used for puffing. The crucial factors affecting the snack purchase were texture and nutrition. The relative crystallinity and retrogradation enthalpy (?H_r) of freeze‐dried pellets increased with increasing the AC. From using a differential scanning calorimeter (DSC), endotherms of pellets were shown only when AC > 0.12%. An amylose–lipid complex was shown in pellets with AC ≥ 9.00%. Relationships between the AC and all puffed product properties were linear. Increasing AC provided greater hardness, fracturability, bulk density, but lower expansion ratio. From the sensory evaluation, the panellists preferred the puffed products with 9.00% AC. Increasing the AC gave higher crispness, hardness, brittleness, air cell opacity and density, but resulted in less puffiness. Thus, the microwave drying has the potential to puff a healthy expanded snack but giving the desirable properties depends on AC.     

The effect of rice bran on physicochemical,textural and glycaemic properties of ready-to-eat extruded corn snacks

In this work, corn extruded snack products were enriched with rice bran (RB) at 10% and 15%. A co-rotating twin-screw extruder was used with a feed moisture content of 16 g 100 g⁻¹, a screw speed of 240 r.p.m. and four heating sections of the barrel (100, 140, 150 and 150 °C). The impact of RB inclusion on nutritional profile, starch digestion, physicochemical and textural properties of snack products was evaluated. RB-enriched extrudates showed a lower specific volume and hardness and higher crispness than control. RB at 15% gave a water-holding capacity lower than control. Rheology of extrudate dispersions indicated an increase in elastic interactions and solid-like behaviour with RB supplementation. Differences in rheological properties resulted in attenuation of predictive glycaemic response for RB-enriched snacks.     

Stability of Tocopherols and Retinyl Palmitate in Snack Extrudates

ABSTRACT: Fish- and peanut-containing half-products were obtained by extruding and drying tocopherol- and retinyl palmitate-fortified mixtures of tapioca starch and minced fish or partially defatted peanut flour (PDPF 60:40, wet basis). Half-products were puffed by deep-fat frying. Vitamins were determined simultaneously at each step of snack production using a direct solvent extraction method. Extrusion significantly reduced the content of tocopherols and retinyl palmitate in both products. Reduction of retinyl palmitate in fish and peanut extrudates during snack production was 48% and 27%, respectively. Final products contained more tocopherol than intermediates because of the high tocopherol content in the frying oil and its uptake.     

Cover Caption

February Online Cover : Close‐up longitude cross‐section of puffed corn and corn‐fish snacks, from “Studying the Effects of Nucleating Agents on Texture Modification of Puffed Corn‐Fish Snack” by Hamid Reza Shahmohammadi, Jamilah Bakar, Russly Abdul Rahman, and Noranizan Mohd Adzhan; p. E182.     

INCORPORATION OF MINCED TROUT (ONCORHYNCHUS MYKISS) INTO EGG-BASED NOODLES

Recovering minced fish from fish frames following filleting operations is a common way to increase fish muscle yield as well as fully utilize aquatic food resources. Therefore, it is important to develop new and feasible applications for minced fish that will add value to fishery products. In this study, washed minced trout (Oncorhynchus mykiss) was incorporated at 10 and 20% flour replacement level into a conventional egg noodle formulation. Textural attributes (by TPA) of cooked noodles were evaluated. In addition, textural, functional and sensory attributes of fried noodles, a snack food item, were also evaluated. Visual color (CIE )‐Lab of fresh noodles containing minced trout was less red and yellow than the control and the overall difference in color (ΔE) increased as the level of minced trout increased. Noodles incorporating 10% minced trout had cooked texture profiles similar to the control; however, there were significant decreases in hardness, gumminess and chewiness in the cooked noodles containing 20% minced trout. For the fried noodles, adding fish tended to reduce the yellow color and yielded a product with texture profiles similar to the control at a 10% substitution level. The experimental and control products were acceptable. Product preference was evenly divided between the control fried noodle and the noodle containing 10% minced trout.     

玉米皮膳食纤维鱼丸的制备

以玉米皮膳食纤维鱼丸的感官评价为指标,分别考察了玉米皮膳食纤维、大豆分离蛋白和蛋清添加量对鱼丸品质的影响。试验结果表明:当玉米皮膳食纤维添加量4%,大豆分离蛋白添加量10%,鸡蛋清添加量12%时,鱼丸品质最佳。在此优化工艺条件下,得到的玉米皮膳食纤维鱼丸,具有口感细腻、滑嫩,弹性好,切面致密均匀存在很少的小洞。     

Enhancing an Extruded Puffed Snack by Optimising Die Head Temperature,Screw Speed and Apple Pomace Inclusion

Extrusion cooking is recognised as a smart technology for food processors. It requires low cost, high temperature, short-time process and few ingredients to create a puffed snack. The only drawback is that it contains multiple parameters that need to be rigorously trialled to develop an optimal process. This study investigated the effects of two extruding parameters (die head temperature and screw speed) and examined the addition of apple pomace into a corn flour-based extruded snack formulation. A response surface design was utilised. A D-optimal design was chosen, which generated 21 combinations; within these combinations, the control formulation existed. Extrudate characteristics, i.e. bulk density and porosity, textural properties, cooked starch properties and moisture, were analysed. Screw speed was found to have the greatest effect on extrudate quality, e.g. bulk density increased as the screw speed increased (p?<?0.001). Both apple pomace addition and screw speed impacted expansion ratio; as they increased, expansion decreased (p?<?0.0001). The optimised and validated formulation contained the following parameter levels: 7.7 % apple pomace, 150 °C die head temperature and a screw speed of 69 rpm. As apple pomace and corn flour are naturally gluten free, the extruded product would appeal to people who suffer from intolerances, allergies and coeliac disease.     

膨化玉米复合粉配方优化及挥发性风味物质分析

目的:通过复配改善膨化玉米粉的风味及冲调性。方法:采用D-最优混料设计,向膨化玉米粉中加入不同比例的膨化小米粉、炒制红米粉、膨化大米粉和膨化黑米粉,从冲调结块率、黏度、感官评分、挥发性风味物质变化等角度对复合粉进行分析评价,并利用气相质谱技术分析不同样品的香味成分。结果:复合粉的配方为膨化玉米粉50.8%、膨化小米粉8.8%、炒制红米粉0.5%、膨化大米粉19.9%、膨化黑米粉20.0%。较单一膨化玉米粉而言,复合粉结块率降低为0.52%、黏度升高为2 880 mPa·s,感官评分87.84分,冲调性能得到极大的改善。复配后的膨化玉米粉具有青香和更浓的坚果香,风味物质增多,其中醛类物质增加最为明显。结论:复配后的膨化玉米粉冲调品质得到改善,挥发性风味物质增加。     

QUALITIES OF EXTRUDED PUFFED SNACKS FROM MAIZE/SOYBEAN MIXTURE

A maize‐based snack was fortified with partially defatted soybean (PDS) at 10, 20 and 30% of total weight and analyzed for physical (expansion ratio, density, color and texture [brittleness, breaking strength and hardness]), chemical and sensory characteristics. Incorporating PDS in a maize‐based snack had a positive effect on chemical properties but had a negative effect on the physical and sensory characteristics. The results showed a protein range of 9.3 ± 0.90% in 100% maize‐based snacks to 19.3 ± 1.03% in 30% replacements with soybean. The overall consumer acceptability test showed a score range between 4.1 ± 0.82 in 30% level of fortification and 8.2 ± 1.04 in 100% maize and 10% fortified extrudate. Panelists perceived the puffed extrudates with 20 and 30% PDS as not puffy or crispy, less acceptable and harder to crack. Up to 20% of PDS could be used in maize‐based puffed extrudates.     

PEO与合成硅酸镁铝凝胶二元体系的助留助滤性能

研究了PEO-合成硅酸镁铝凝胶系统以及不同PEO用量对系统留着率的影响,并将PEO-合成硅酸镁铝凝胶体系与PEO-凹凸棒土、PEO-膨润土系统的助留助滤效果进行了比较。对PEO-合成硅酸镁铝系统改善滤水性能,提高填料留着率及成纸白度方面的影响进行了探讨。结果表明：PEO-合成硅酸镁铝凝胶系统在PEO用量为0.16kg/t,合成硅酸镁铝凝胶为10kg/t时,细小纤维留着率在73%以上,填料留着率在45%以上,同时打浆度能够下降20°SR。综合比较,PEO-合成硅酸镁铝凝胶二元助留体系的助留助滤效果优于PEO-凹凸棒土二元体系和PEO-膨润土二元体系。     

Effect of Cultivars and Thermal Processing with Salt Solutions on the Textural Attributes (Hardness,Chewiness and Rate of Softening) of Potatoes (Solanum Tuberosum L.)

The change in textural attributes (hardness, chewiness and rate of softening) of three potato cultivars (Russet Burbank, Desiree and Sebago) was investigated. Uniform cylindrical samples (35-mm diameter and 3-mm thick) were prepared and exposed to different thermal processing regimes including; heating at 85°C, 95°C in water and steaming (100.2°C). The effect of salt on these textural attributes was also investigated using different salt concentrations (1.5%, 3% and 6% (w/w) NaCl). After thermal treatments the samples were subjected to texture profile analysis. The instrumental textural attributes were greatly affected by the cultivars and the thermal processing regimes. The change in textural attributes upon steaming was only marginally different compared to that at 95°C in water. Low concentrations of salt (1–3%) were found to accelerate the softening of the texture in these cultivars especially at lower temperatures. The textural attributes were modelled using a two-parameter reaction kinetics model. There was reasonable agreement by the model findings on the textural attributes prepared from all the thermal processing regimes and in presence and absence of (within average absolute error of 1.9–7%). Further, the model indicated that the order of reaction varied from 1.15–2.18 indicating that the changes in textural attributes in these thermal processing regimes followed higher reaction orders.     

CELLULAR STRUCTURE OF PEANUT-BASED EXTRUDED SNACK PRODUCTS USING SCANNING ELECTRON MICROSCOPY

A mixture of partially defatted peanut flour (12% fat) and rice flour was extruded to produce indirectly, puffed extrudates using a corotating twin-screw extruder. Extrudates were dried to obtain half-products of 11-12% moisture content, and the half-products were expanded by deep-fat frying. The effects of three levels of peanut flour (30, 40, and 50%), screw speed (200, 300, and 400 rpm) and feed rate (4, 5, and 6 kg/h) were studied by characterizing the cellular structure of expanded snack products using Scanning Electron Microscopy (SEM). Average cell size (mm²) and the number of cells per unit area (cm²) were determined from the interior cross-section area of snack products. Those parameters were influenced mainly by the level of peanut flour followed by screw speed and feed rate. Increasing peanut flour from 40 to 50% produced less puffed final products resulting in small cell size compared to snacks of 30 - 40% peanut flour. The maximum cell size was produced in the snack products extruded with peanut flour of 30 - 40% at screw speed of 250 - 330 rpm and feed rate of 4.7 - 5.7 kg/h. While the number of cells was relatively similar regardless of screw speed and feed rate, increasing peanut flour increased the number of cells. The cell walls became thicker with increasing feed rate.     

Sustainable snack products: Impact of protein- and fiber-rich ingredients addition on nutritive,textural, physical,pasting and color properties of extrudates

The objective of this study was to explore the feasibility of incorporating mechanically deboned poultry meat (MDPM) and brewers spent grain (BSG) to corn based extruded snack products. The addition of protein- and fiber-rich ingredients creates nutritionally fortified snack product, however with lower quality of physical and textural characteristics and altered color. Therefore, the impacts of different MDPM (from 4 to 12%) and BSG (from 10 to 30%) concentrations and varying screw speeds (500, 700, 900 rpm) on physico-chemical properties of extruded snack products were investigated. Through optimization, with defined desired nutritional and physical characteristics and within the investigated range of input variables (MDPM, BSG and screw speed), the optimal product was defined. The optimized snack formulation contained 4% MDPM and 14.8% BSG, and it was produced at 900 rpm screw speed. Furthermore, the analysed parameters of the optimal snack demonstrated good agreement with the predicted values, indicating successful optimization.     

Effect of Water Activity on the Sensory Crispness and Mechanical Deformation of Snack Food Products

Potato chips, popcorn, puffed corn curls, and saltines were equilibrated to various water activities (a_w) over saturated salt solutions. Sensory panels determined the crispness and textural hedonic quality of the humidified products by the magnitude estimation technique coupled to a verbal concept scale. Critical water activities (a_c), where the products became organoleptically unacceptable, generally fell in the 0.35–0.50 a_w range. Instron analyses showed that the force-deformation curve changed distinctly near the a_c for saltines and puffed corn curls, while the curve changed more gradually with increasing a_w for popcorn. Potato chips did not produce a consistently shaped force-deformation curve. The cohesiveness value of popcorn was found to be a good indicator of its sensory crispness.     

Novel Products from Underutilized Fish Using Combined Processing Technology

Mincing or surimi-processing, followed by fermentation, extrusion and intermediate moisture food (IMF) processing were combined to investigate new ways to create fish protein based snack foods. A dough of fermented fish (minced or surimi), wheat flour, corn starch, and water was extruded and subsequently dried resulting in an IMF product at pH 5.2, water activity 0.90 and moisture about 30%. The products had a chewy texture, were shelf-stable and could be processed into flavored, high-protein snack foods.     

MICROSTRUCTURAL CHARACTERISTICS AND COMPRESSION RESISTANCE AS INDICES OF SENSORY TEXTURE IN A CRUNCHY SNACK PRODUCT

Identically formulated drum dried and cold formed half-products were puffed in hot air or by frying to determine microstructure-texture relationships. Structural attributes measured were cell size (CS), number of cells per unit area (CN), cell wall thickness (CW) and product specific volume (SV). Sensory attributes of crunchiness, hardness and density were also evaluated. Puffed product microstructure depended more on the half-product preparation process than the method of puffing. Similarly prepared half products had the same microstructural attributes whether fried or hot air puffed. Sensory scores for crunchiness were not significantly different among all samples but scores for hardness and density were significantly different between hot air puffed and fried products even when microstructural attributes were similar. Higher compression force values reflected lower sensory scores for crunchiness and hardness of puffed products. Compression force was significantly correlated with microstructural attributes of CS, CW and SV.