Effect of extrusion conditions on the physicochemical properties of a snack made from purple rice (Hom Nil) and soybean flour blend

Soy flour was added at levels of 5%, 10%, and 15% of Hom Nil rice flour for extrusion at 190 °C barrel temperature and 350 rpm screw speed. The extruded snack qualities decreased inversely with soy flour. However, product qualities were considered to be optimised when soy flour at 5% was added. The effect of feed moisture content (15, 17, 19 g (100 g)^?1 wb), barrel temperature (150, 170, 190 °C) and screw speed (350, 400, 450 rpm) on physicochemical properties of the snack were then investigated. The physicochemical properties of the product including expansion ratio, density, water absorption index (WAI), water solubility index (WSI) and hardness were evaluated. All properties were related, as linear equations, in terms of feed moisture content, barrel temperature, screw speed with relative correlation (R²) at 0.83–0.94. The snack properties along with consumer acceptance were all highest when the extruded condition were 15 g (100 g)^?1 wb feed moisture content, 170 °C of barrel temperature and 450 rpm of screw speed.     

Survey of undeclared egg allergen levels in the most frequently recalled food types (including products bearing precautionary labelling)

Since the number of recalls involving undeclared allergens is commonly associated with bakery and snack foods, we aimed to determine the frequency of egg allergens in a large number of these products using two commercial enzyme-linked immunosorbent assay (ELISA) methods. Samples were chosen that either had no egg identified on the product label or which had an egg precautionary statement. Among all samples, egg protein was detected in 5% of products using a Morinaga (MO) kit and 1% of products using a R-Biopharm (RB) kit. For bakery samples, egg protein was detected in 6% of 363 samples with no precautionary labelling (6% by MO and 1% by RB kit) and 12% of 80 samples which had precautionary labelling. For snack samples, egg protein was detected in 2% of 371 samples with no precautionary labelling (2% by MO and < 1% by RB kit) and 5% of 21 samples which had precautionary labelling. The disagreement rates between two methods were 5.2% for bakery products and 2.6% for snack products. The sample repeatability was at an acceptable level for bakery (< 12.5%) and snack foods (< 7.5%) for each method. The relative standard deviation between test kits was high (103.1%) for bakery foods. Four bakery products without precautionary labelling had a higher level of egg protein per serving compared with the eliciting dose (ED₁₀ of 3.7 mg protein) for egg allergic patients. These results highlight the fact that detection methodology plays a vital role for accurate labelling control and mitigation of risk for egg allergic consumers.     

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.     

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.     

Effects of cricket powder on selected physical properties and US consumer perceptions of whole-wheat snack crackers

Successful introduction of insect consumption to a reluctant US population requires novel insect-based foods that are responsive to consumers’ expectations of sensory quality. Based on our ‘product appropriateness’ data, snack crackers were formulated with increasing levels of cricket powder (0%, 5%, 10%, 15%, and 20%) in substitution of whole-wheat flour. Colour, texture, flavour and overall perceptions of snack crackers were evaluated by 150 US consumers in terms of preference (2-alternative choice), degree of liking (9-point scale) and acceptability (yes/no). Flavour liking was most highly correlated with overall liking (r = 0.93). Instrumental analyses indicated that increasing cricket powder resulted in darker and harder crackers, negatively impacting colour and texture preference at 5% and 15% cricket powder addition, respectively. Snack crackers remained acceptable at 15% wheat flour substitution (80% acceptability; mean overall liking = 5.5). However, to promote future consumption, an upper limit of 7.9% cricket powder addition is recommended until sensory quality can be improved.     

In vitro gastrointestinal digestion of mango by-product snacks: Potential absorption of polyphenols and antioxidant capacity

Mango by-products are considered cheap sources of valuable foods and nutraceutical ingredients. In this work, antioxidant capacity (AOX), and potential absorption ability (PAA) of extractable polyphenols (EP) from mango by-product snacks (MB-S) were evaluated at different stages of in vitro gastrointestinal digestion. A wheat and oat-based control snack and three MB-S formulations (F1, F2 and F3) were prepared. Mango by-products were added at the expense of wheat in MB-S (paste-peel-seed): F1 (70-30-0), F2 (70-15-15), F3 (70-7.5-22.5). The highest release of polyphenols was observed after the gastric digestion. In the intestinal stage, MB-SF1 was the snack with the highest EP content (23.39 mg GAE/g db), two times greater than the control. Gallic acid and mangiferin were the main polyphenols identified in MB-S. The incorporation of mango seed in the MB-S reduced the polyphenols PAA by 10.29%. However, compared with the control snack, consumption of 30 g MB-SF1 provided additional 45 mg polyphenols.     

Inulin and maltodextrin can replace fat in baked savoury legume snacks

A baked yellow split pea cracker was developed with fat replacement (0%, 25%, 50%, 75% and 100%) using inulin, hydroxypropyl methylcellulose and maltodextrin. Effects of fat replacement on physical (water activity, moisture content, colour and hardness), nutritional properties and consumer acceptance (nine‐point hedonic rating) of snacks were investigated. Water activity (0.15–0.32) and moisture (1.28–3.16%) readings were consistent, and products were considered shelf stable. High levels of fat replacement (100%) were detrimental to snack colour and hardness. Snacks with 75% fat replacement using inulin and maltodextrin received similar mean overall acceptability scores (6.40 ± 1.36 and 6.26 ± 1.37, respectively) to the control and a similar commercial product. These snacks were eligible to claim that they were a ‘good source’ of protein (requirement; ≥10 g per serve) and an ‘excellent source’ of dietary fibre (requirement; ≥7 g per serve) while providing ‘reduced’ fat content (≤25% than reference food) based on the Australian Food Standards Code.     

Influence of canola-olive oils, rice bran and walnut on functionality and emulsion stability of frankfurters

Fat content of frankfurters (20 g/100 g) was replaced with canola and canola-olive oils. Rice bran (RB) and walnut (WE) were added (2.5 g/100 g) to emulsions as macronutrients. Changes in energy values, color, emulsion stability and lipid oxidation of frankfurters during storage were investigated. ANOVA model was highly significant for color parameters and energy values (P < 0.001). The canola-olive oil replacement led to a high capacity to hold water and fat exudates in frankfurters, reporting higher emulsion stabilization parameters than regular frankfurters. The addition of RB led to an increase of cooking and fat exudates, indicating high emulsion instability possible due to interactions between RB fiber and fat-protein binders. Walnut addition reported low cooking loss values, and a significant capacity for emulsion stabilization in comparison with regular and RB frankfurters. Lipid oxidation increased from days 0-7 in all frankfurters, declining afterwards until end of storage. TBARS was not influenced by type of emulsions control, but significant (P < 0.05) differences were observed in vegetable oil emulsions made with RB; as well as between RB and WE added to either vegetable oil emulsions. These results suggest the use of these natural ingredients as valuable promoters of healthy meat products.     

The effects of ultrasonic/microwave assisted treatment on the properties of soy protein isolate/titanium dioxide films

Soy protein isolate (SPI, 5.0 g/100 mL,) films embedded with nano-TiO₂ (0, 0.5, 1.0, 1.5 and 2.0 g/100 mL) were prepared by solution casting and modified by ultrasonic/microwave assisted treatment (UMAT). The effects of nano-TiO₂ content and UMAT time on the films' physical properties and structure were investigated. Incorporation of nano-TiO₂ significantly enhanced films' mechanical properties and barrier properties, because of the intermolecular force between nano-TiO₂ and SPI. UMAT time ≤20 min obviously improved films' tensile strength values (15.77 MPa, 245% higher than the control), and reduced water vapor permeability (1.8457 × 10⁻¹¹ g cm⁻¹ s⁻¹ Pa⁻¹, 72.11% lower than the control) and oxygen permeability values (0.8897 × 10⁻⁵ cm³ m⁻² d⁻¹ Pa⁻¹, 57.66% lower than the control). SEM images also revealed a more compact and dense structure of films when UMAT time ≤20 min. Films' water adsorption properties were evaluated. GAB and Henderson models exhibited the best to fit experimental data, thus it was predicted that films (1.5 g nano-TiO₂/100 ml) could be stable at low moisture content (0.27 kg of water/kg dry mass).     

Physicochemical,microbiological and sensory characteristics of snacks developed from broken rice grains and turmeric powder

The aim of the present study was to develop extruded snacks from broken rice grains (BRG) and turmeric powder (TP). Different levels of substitution of BRG by TP (0%, 2%, 4%, 8% and 10% w/w) were used. Snacks were processed in a single-screw extruder with three heating zones (41, 61 and 84 °C, respectively), using a helicoidal grooved extrusion sleeve, a 4 mm (diameter) matrix, 3:1 screw compression ratio, screw rotation of 3600 ×  g and a feed rate of 335 g min⁻¹. Snacks were evaluated for their physicochemical, microbiological and sensory characteristics; as well as for the chemical composition, phenolic compounds and the antioxidant capacity of the selected savoury snack formulation. The selected snack, with the physical characteristics closest to the traditional corn product, was obtained with 6% substitution of BRG by TP and was constituted by 7.76% protein, 4.78% lipid, 5.84% dietary fibre, 75.3% available carbohydrates, and 174.75 mg gallic acid equivalent per100 g and 6.52% of DPPH• scavenging capacity. The selected snack was shown to be feasible, once TP is an ingredient that aggregates sensory (colour and taste), nutritional (dietary fibres and total energy value) and functional (antioxidants) values to the BRG-based snack, being an alternative for the production of gluten-free snacks.     

Novel use of Acacia senegal (Super Gum™) and Anogeisus latifolia (Gatifolia SD) as functional ingredients in extruded snack products: Their role in manipulating product characteristics and modulating the potential glycaemic response of snack foods

Acacia senegal (in the form of Super Gum™) and Anogeissus latifolia (in the form of gum Gatifolia SD) were used in the manufacture of ready to eat extruded cereal snack products. Inclusions rates were 0, 5, 10 and 15% w/w replacement levels for wheat flour from a control recipe. The inclusion of Super Gum™ and Gatifolia increased product expansion and reduced product density compared to a cereal flour based control snack product. Inclusion of the gum materials also decreased the hardness of the snack products whilst increasing the crispiness of the product (number of fracture peaks recorded during axial compression of samples). Glucose area under the curve (AUC) measurements obtained using in vitro digestion procedures illustrated that the potential glucose release of snack products was reduced by more than 30% by the inclusion of Gatifolia and Super Gum™ at 15% w/w compared to the control sample. Such a reduction in potential glucose release was not dose responsive. These results illustrate a potential nutritional benefit of the utilisation of Gatifolia and Super Gum™ in the ready to eat snack food sector of the food industry.     

Effect of processing conditions on the stability of annatto (Bixa orellana L.) dye incorporated into some foods

Annatto dye is an orange-yellow pigment extensively used in dairy products. Studies were carried out to determine the stability of bixin (oil-soluble dye) during different treatments and processing in traditional foods of India. The annatto dye was exposed to heat treatments in a baking oven at 100, 150 and 180 °C for time periods up to 60 min; deep fat heating at 160, 180 and 200 °C for periods ranging from 30 to 120 s; microwave oven at 300 and 700 W for periods ranging from 15 to 60 s; and in a pressure cooker for a 15-min period. The losses in bixin concentration during these experiments were compared with the losses of bixin in the preparation of products like cakes, chegodis, biscuits and fried rice. The mass fractions of bixin lost were maximum when the dye was exposed directly to heating in a baking oven (0.54) and in deep fat heating (0.47). The mass fraction of bixin lost was 0.30 in cakes and negligible losses were observed in biscuits (0.015). In case of the deep fat fried snack, the dye leached in to the oil, which resulted in maximum loss (0.65). Microwaves did not affect the bixin in the dye when exposed directly or in the products. Pressure cooking resulted in mass fractions of bixin lost (0.25–0.33) comparable to those of other products.     

Gluten‐Free Snacks Using Plantain–Chickpea and Maize Blend: Chemical Composition,Starch Digestibility,and Predicted Glycemic Index

An increase in celiac consumers has caused an increasing interest to develop good quality gluten‐free food products with high nutritional value. Snack foods are consumed worldwide and have become a normal part of the eating habits of the celiac population making them a target to improve their nutritive value. Extrusion and deep‐frying of unripe plantain, chickpea, and maize flours blends produced gluten‐free snacks with high dietary fiber contents (13.7–18.2 g/100 g) and low predicted glycemic index (28 to 35). The gluten‐free snacks presented lower fat content (12.7 to 13.6 g/100 g) than those reported in similar commercial snacks. The snack with the highest unripe plantain flour showed higher slowly digestible starch (11.6 and 13.4 g/100 g) than its counterpart with the highest chickpea flour level (6 g/100 g). The overall acceptability of the gluten‐free snacks was similar to that chili‐flavored commercial snack. It was possible to develop gluten‐free snacks with high dietary fiber content and low predicted glycemic index with the blend of the 3 flours, and these gluten‐free snacks may also be useful as an alternative to reduce excess weight and obesity problems in the general population and celiac community.     

Characteristics and nutritional value of biscuits fortified with debittered salmon (Salmo salar) frame hydrolysate

Effect of debittered salmon frame hydrolysate (DSFH) at various levels (0, 5, 10, 15, 20 and 25 g/100 g) on physicochemical, textural, sensory and nutritional properties of biscuits was investigated. The highest thickness was obtained for the sample with 25 g/100 g DSFH (P < 0.05). There was no difference in diameter among all the biscuit samples (P > 0.05). The samples added with DSFH had lower weight, water activity and moisture content than the control (CONT, without DSFH) (P < 0.05). DSFH at 15 g/100 g showed no detrimental effect on sensory properties of resulting biscuits (DSFH-15). The DSFH-15 biscuit showed reduction in cutting force and fracturability. Scanning electron microscopic and cross-sectional images showed that DSFH-15 biscuit had more porous structure, compared to the CONT. The biscuits fortified with 15 g/100 g DSFH had higher protein but had lower energy value, fat and carbohydrate content than the CONT.     

Physical and nutritional properties of extruded products based on whole grain with the addition of wild legumes (Vicia lutea subsp. lutea var. hirta and Vicia sativa subsp. sativa)

Flour blends based on whole corn and rice with two added wild legumes at 15% level of cereal replacement were extruded to produce whole grain snacks. Extrusion temperature was 175 °C, and the moisture content was adjusted to 14%. The extruded products were evaluated for their physical, chemical and nutritional properties. Results showed that the addition of legumes produces a decrease in expansion in rice‐containing samples and an increase in solubility in corn‐containing samples. With only 15% of legume added to cereal, a significant increase in protein content and quality was obtained. An increase in fibre, polyphenol, iron and zinc content was also obtained. Protein digestibility was in the range of 81.8–85.3%. Mineral availability ranged from 6.4 to 16.3% for iron and 10–16.3% for zinc. The performance of each mixture during extrusion and the physical properties of the extruded products were considered to be similar to those expected for snack‐type products and described in the literature.     

Effects of extrusion conditions on system parameters and physical properties of a chickpea flour-based snack

Response surface methodology (RSM) was used to study the effects of feed moisture content (16–18%), screw speed (250–320 rpm), and barrel temperature (150–170 °C) on extruder system parameters (product temperature, die pressure, motor torque, specific mechanical energy, SME) and physical properties (expansion, bulk density, hardness) of a chickpea flour-based snack. Second-order polynomials were used to model the extruder responses and product properties as a function of process variables. Product temperature and die pressure were affected by all three process variables, while motor torque and SME were only influenced by screw speed and barrel temperature. All three variables affected product responses significantly. Desirable products, characterized by high expansion ratio and low bulk density and hardness, were obtained at low feed moisture, high screw speed and medium to high barrel temperature. It was demonstrated that chickpeas can be used to produce nutritious snacks with desirable expansion and texture properties.     

Effect of high power ultrasonic treatment on whey protein foaming quality

High power ultrasonic energy at 20%, 40% and 60% amplitude was applied on whey protein suspension at concentrations of 100, 150 and 200 g kg^?1 for 5, 15 and 25 min to improve its foaming quality. Ultrasound‐treated whey protein suspension at 200 g kg^?1 showed improvement in terms of increased foaming capacity by 18%, foam stability by 35%, consistency index by 18%, storage modulus by 17%, loss modulus by 26% and viscosity by 21% compared with untreated whey protein. For maximally ultrasound‐treated samples of 60% amplitude treated for 25 min, the improved whey protein foams also had a 46% increase in the number of more evenly distributed fine bubbles which had a size smaller than 0.0025 mm³ as imaged using X‐ray microtomography.     

Fluorescence characteristics of sodium fluorescein–rose bengal ophthalmic solution mixtures

PurposeTo assess fluorescence emission properties of sodium fluorescein–rose bengal mixtures in buffered aqueous solution.MethodsSolutions of sodium fluorescein (NaFl) or rose bengal (RB) or mixtures of these two chemicals were prepared over a range of dilutions in 1% NaCl with 10 mM phosphate buffer to give a pH of 7.5 at room temperature. Absorbance and fluorescence spectra were recorded in 10 mm path length cuvettes.ResultsThe fluorescence emission from NaFl extends between 480 and nearly 600 nm, a spectral range that is also covered by the absorbance of RB (between 500 and 580 nm). With very dilute solutions of NaFl (less than 0.002%), an apparent total quenching of its fluorescence can occur in the presence of 0.01% RB, with a proportionate decrease at lower concentrations of RB.ConclusionsThe presence of RB in an aqueous solution of NaFl at physiological pH appears to act in a similar way to a barrier filter, resulting in the quenching of the measurable fluorescence from NaFl. It remains to be established how substantial or significant such an effect might be if a mixture of NaFl and RB as used as part of the examination of the external eye.     

Carvacrol-loaded chitosan nanoparticles maintain quality of fresh-cut carrots

The effects of carvacrol-loaded chitosan-tripolyphosphate nanoparticles (Np-EO) on the physicochemical, sensory and microbial quality of fresh-cut (FC) carrot slices stored up to 13 days at 5 °C were studied. Np-EO was compared to samples treated by NaOCl (100 mg L^− 1), Np (chitosan-tripolyphosphate nanoparticles without carvacrol) or individual chitosan (0.5%) and carvacrol (0.5%) solutions. Np-EO achieved the best sensory scores also avoiding carvacrol-related off-flavours found with the carvacrol solution. Furthermore, whitening of FC carrot slices was highly reduced in Np-EO samples. Np-EO reduced microbial levels in FC carrot slices by 0.6–3.0 log units on processing day compared to untreated (control) samples. Np-EO allowed to reduce the microbial growth in FC carrot slices during the first 9 days of storage similarly to carvacrol solution. Furthermore, Np-EO highly controlled microbial loads at the end of storage showing 2.3 (lactic acid bacteria), 6.1 (yeasts and moulds) and 5.1–5.4 (mesophiles, psychrophiles and Enterobacteriaceae) lower log CFU g^− 1 units compared to control samples. Conclusively, Np-EO highly maintained microbial (2–6 lower log CFU g^− 1 units compared to control), sensory (up to 2.5 better scores than control) and physicochemical quality of FC carrot slices than control for 13 days at 5 °C.Industrial relevanceNatural essential oils industrially extracted from plants are potential alternative substances with high antimicrobial properties when tested in vitro. However, their microbicidal efficacy is greatly reduced due to their low solubility in washing solutions of fresh-cut products. Accordingly, chitosan-tripolyphosphate nanoencapsulation of essential oils such as carvacrol is a great opportunity to increase the antimicrobial properties of carvacrol to be used in fresh-cut fruit and vegetables alternatively to conventional NaOCl sanitation.     

The advantage of using extrusion processing for increasing dietary fibre level in gluten-free products

Gluten-free products generally are not enriched/fortified and frequently are made from refined flour and/or starch. Such products have been found to provide lower amounts of total dietary fibre than their enriched/fortified gluten-containing counterparts.The objective of this study was to increase the level of total dietary fibre in gluten-free products by using extrusion technology and by incorporating a number of different fruits and vegetables, such as apple, beetroot, carrot, cranberry and gluten-free Teff flour cereal. The materials were added at the level of 30% into the gluten-free balanced formulation (control) made from rice flour, potato starch, corn starch, milk powder and soya flour. Different process conditions, such as water feed rate 12%, solid feed rate 15–25 kg/h, screw speed 200–350 rpm, barrel temperatures: 80 °C at feed entry and 80–150 °C at die exit were used. Pressure, material temperature and torque were monitored during extrusion runs. The relationships and interactions between raw ingredients, extrusion processing parameters and resulting extrudate nutritional and textural properties were investigated.The results of this study clearly show that extrusion technology has the potential to increase the levels of total dietary fibre in gluten-free products made from vegetables, fruits and gluten-free cereals.