Impact of dietary fibre‐enriched ready‐to‐eat extruded snacks on the postprandial glycaemic response of non‐diabetic patients

Food intervention is a financially sensible way for prevention and treatment of diabetes. Extruded snack foods are considered high glycaemic products. Our previous research illustrated that postprandial glycaemic responses to snacks are manipulated by altering dietary fibre and starch contents. The current research assessed the effect of psyllium and oat bran on postprandial glycaemia and in vitro digestibility. Addition of psyllium fibre to extruded snack products significantly reduced both the in vitro and in vivo glycaemic responses of products compared to a control snack product recipe. Oat bran inclusion reduced in vitro starch digestibility but not in vivo glycaemic response. The inclusion of oat bran into the snack products appeared to extend the glycaemic response of individuals compared to the control snack, suggesting a possibility of prolonging glucose release and potentially affecting satiety responses. The positive effect in attenuating glucose response means that psyllium fibre could be a target for inclusion by the snack food industry to effectively manipulate postprandial glucose response of individuals.     

Physical evaluation of a maize‐based extruded snack with curry powder

Response surface methodology was used to analyze the effect of screw speed (200–280 rpm), feed moisture (13.0–17.0%, wet basis), and curry powder (6.0–9.0%) on the bulk density, lateral expansion, and firmness of maize‐based extruded snack with curry powder. Regression equations describing the effect of each variable on the responses were obtained. Responses were most affected by changes in feed moisture followed by screw speed and curry powder (p < 0.05). Lateral expansion increased linearly as the amount of curry powder added was increased whereas a quadratic increase was obtained in lateral expansion with decreasing feed moisture. The firmness of samples was increased with an increase in feed moisture. The bulk density of samples was increased with increasing feed moisture and screw speeds. Radial expansion was found to be a better index to measure the physical properties of the extruded product indicated by a higher correlation coefficient.     

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.     

Chemical composition and physical properties of extruded snacks containing crab‐processing by‐product

The crab‐processing industries generate millions of pounds of by‐product annually, which results in a loss of edible product and presents a considerable waste disposal problem. The purpose of this research was to investigate the use of crab‐processing by‐product (CB) in the development of a calcium‐rich expanded snack. The specific objectives were to examine the effects of type of CB (wet or dry), feed composition and screw speed (150 or 250 rpm) on selected properties of extruded snacks. Product formulations consisting of 0–400 g kg^?1 CB combined with corn meal and potato flakes were processed in a twin‐screw extruder. The resulting extrudates were analysed for proximate and mineral (calcium, sodium) composition, pH, water activity (a_w), total plate count, bulk density, expansion ratio and colour. Both CB type and level of incorporation had significant effects (P < 0.05) on the calcium content, expansion ratio, bulk density and pH of the extrudates. Increasing the CB level resulted in increased calcium content (from 5.1 to 52.4 mg g^?1) and pH (from 6.1 to 8.8). Screw speed had no significant effects (P > 0.05) on expansion ratio and bulk density. A high processing temperature (157 °C) and low a_w resulted in undetectable microbial growth on the extrudates. This research demonstrates that ground crab‐processing by‐product can be successfully incorporated into an expanded snack product. Further research will evaluate consumer response to this novel value‐added product. Copyright © 2003 Society of Chemical Industry     

Effects of ionising irradiation on quality and sensory attributes of ready‐to‐eat dry fermented sausages enriched with folic acid

Dry fermented sausages have been manufactured with different concentrations of folic acid (FA) (0.6, 1.2 and 2.4 mg per 100 g of original mixture). Then, they were prepared as ready‐to‐eat meat products by using E‐beam radiation (2, 3 and 4 kGy) to increase their safety. The stability of this vitamin as well as the physico‐chemical properties, microbiological counts, colour, texture and sensory properties of the sausages was studied after irradiation. The more important changes were observed in hardness, which increased with increasing FA amount; in contrast, colour was similar in all batches, independently of FA concentration or irradiation doses applied. The sensory properties of these products were judged acceptable to tasters, although significant differences were observed between the taste of nonirradiated and irradiated samples with 3 kGy. The ionising treatment caused a decrease of 15–29% in the FA content only at the highest dose (4 kGy). Despite this loss, this new product is suitable for assuring the daily intake of FA recommended as healthy (400 μg).     

Thermo‐rheological and functional properties of gamma‐irradiated wholewheat flour

The effects of different doses (0, 0.5, 1, 2.5, 5 and 10 kGy) of gamma irradiation on the thermal, rheological and functional properties of the wholewheat flour were evaluated. Water and oil absorption capacity of the flour increased from 85.92% to 91.44% and 1.10 to 1.91 g g^?1 of flour, respectively, with increase in irradiation dose. The dough development time decreased with dose from 4.0 to 3.0 min. The transition temperatures (T_o, T_p and T_c) decreased as the dose increased; enthalpy of gelatinisation (?H) decreased from 5.18 to 4.27 J g^?1 with dose. The flow behaviour showed a shear‐thinning behaviour, and the hysteresis area decreased with dose. The structural recovery decreased with dose. FTIR did not show formation of any new chemical groups.     

Comparison of physicochemical properties,antioxidant and metal‐chelating activities of protein hydrolysates from Phaseolus lunatus and hard‐to‐cook Phaseolus vulgaris

Limited and extensive hydrolysates were obtained from Phaseolus lunatus (LHl and EHl) and hard‐to‐cook Phaseolus vulgaris (LHv and EHv) using the enzymes Flavourzyme^®, Alcalase^®, Pancreatin^® and a sequential Pepsin^®–Pancreatin^® system. Degrees of hydrolysis varied from 8.32% to 31.60%. SDS‐PAGE of extensive hydrolysates showed molecular weights smaller than limited hydrolysates. Differential scanning calorimeter (DSC) analysis of LHl and EHl revealed the presence of two endothermic transitions; LHv and EHv had only one. LHv presented a higher content of hydrophobic amino acids whose surface hydrophobicity was 12.17. Functional properties such as nitrogen solubility, foaming capacity and emulsifying activity index in LHv were better than LHl at different pH evaluated. However, the latter showed better foaming stabilities. Amino acids such as His, Tyr, Trp and Arg were observed in greater amounts in both extensive hydrolysates. 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging and metal‐chelating activities in EHv and EHl increased significantly compared to the source material.     

Physicochemical and microbial properties of nanopowdered peanut sprout‐supplemented Caciocavallo‐like cheese during ripening

This study was carried out to investigate the physicochemical and microbial properties of nanopowdered peanut sprout‐supplemented Caciocavallo‐like cheese (NPSCC) during ripening at 14 °C for 6 weeks. The total phenol contents and lactic acid bacteria counts in NPSCC were significantly higher than those in the control, indicating that nanopowdered peanut sprout could potentially be used as a prebiotic and potential source of dietary antioxidants in the dairy products. Thiobarbituric acid values of the cheese were significantly decreased and the production of short‐chain free fatty was not significantly different when nanopowdered peanut sprout was added into the production of Caciocavallo‐like cheese.     

Development of a long‐life vacuum‐packaged ready‐to‐eat meat product based on a traditional Portuguese seasoned meat

Carne do alguidar is a Portuguese traditional pork fried meat, usually manufactured for self‐consumption purposes. This study developed a ready‐to‐eat (RTE) meat product, to meet today's consumers’ convenience, manufactured at the industrial scale evaluating its quality and shelf life, assessing the effect of vacuum packaging and the use of an antioxidant (50 ppm BHT) to enhance oxidative stability. Physicochemical and microbiological parameters were assessed, and a sensory analysis was performed. Interestingly, no significant differences were recorded between control (non‐BHT) and antioxidant (BHT) samples. Microbiological counts remained at low levels throughout the storage period, ensuring the product's required microbiological quality. At later storage stages, higher values of thiobarbituric acid‐reactive substances arose and off flavours and aromas were perceived. Still, overall appreciation was not affected until 12 months of storage and a significant depreciation was perceived only after 15 months. Fibrousness and rising of off flavours were negatively correlated with overall appreciation.     

Role of protein oxidation in the nutritional loss and texture changes in ready‐to‐eat chicken patties

The oxidative damage to proteins during processing of ready‐to‐eat chicken patties and its impact on the nutritional value and texture properties of the product were assessed. The effect of cooking techniques (boiling, roasting and grilling) and microwave reheating (600 mW per 1 min) after 7 and 14 days of cold storage (+4 °C) were studied. Cooking methods had an effect (P < 0.05) on most protein oxidation parameters, including protein depletion of tryptophan, thiols, protein carbonylation and formation of cross‐links. Overall, the succeeding chilled storage led to an aggravation of the oxidative damage which occurred along with hardness increase and impaired digestibility. Microwave reheating had contradictory effects on protein oxidation parameters. An increase in protein carbonylation occurred along with a cleavage of disulphide bonds that would explain a decrease in hardness. This study illustrates to which extent the oxidative damage to meat proteins affects protein quality and nutritional value of a severely processed meat product. The impact of assorted cooked procedures on these events is also discussed.     

The effect of long‐term storage on amino acid content of ready‐to‐eat entrées

The effect of 24‐month storage at three different temperatures (6 ± 2 °C, 26 ± 2 °C, 37 ± 2 °C) on quality of three types of ready‐to‐eat entrées (MRE) was evaluated by means of amino acid, ammonia, moisture and crude protein contents. Spicy risotto, Pork meat with carrots and potatoes and Pork goulash with pasta, that are included into the Czech combat rations, were selected for the experiment. During storage, all the explored samples did not significantly differ in moisture and crude protein content. Higher losses of amino acids (e.g. sulphuric amino acids, lysine, leucine) were detected with the increasing storage time and temperature. Growing losses of amino acids resulted in rising ammonia content as a product of amino acid degradation process. The biological value expressed by essential amino acid index declined with higher temperature and longer time of storage. The dependence of amino acid losses on moisture content was observed, too.     

Physicochemical properties of low‐fat soft cheese Turkish Beyaz made with bacterial cellulose as fat mimetic

The effects of incorporating various concentrations of bacterial cellulose (BC) (1.7 and 3.5% w/v) on the physicochemical and sensorial properties of low‐fat soft cheese Turkish Beyaz were investigated during a 60‐day ripening period. Control cheeses were produced using nonfat, half‐fat (1.7% fat) and full‐fat milk, for comparison. Depending on changing fat percentage, some physicochemical properties of cheeses, such as moisture, pH and salt showed significant differences, but BC had no influence on these properties. Fat content and BC altered the textural and sensory properties. These results indicated that BC improved the quality of reduced‐fat and low‐fat Turkish Beyaz cheeses.     

Antioxidant potential and quality characteristics of Mediterranean fruit‐based extruded snacks

‘Mediterranean snacks’ (dried fruits and nuts as principal ingredients), a little known food product with a high nutritional value, might be considered a good alternative for consumers looking for healthy snacks. The aim of this research was to determine the physicochemical properties and nutritional value of this type of food stuff (traditionally called ‘fruit cakes’ in Mediterranean countries) and to evaluate their phenolic content and antioxidant activity. All the fruit‐based extruded snacks studied are shelf‐stable at room temperature (because of their pH and water activity values). The final product has a low moisture (<32%) and high sugar content (>30%), the only sugars being those naturally present in the food. All the fruit‐based extruded snacks had a dietary fibre content higher than 10% (high‐fibre foods). Date extruded snack and apricot extruded snack showed the highest total phenolic and flavonoid content and also the highest antioxidant activity as determined by the DPPH and FRAP methods.     

Ready‐to‐eat snack products: the role of extrusion technology in developing consumer acceptable and nutritious snacks

Consumer appeal for ready‐to‐eat (RTE) products is forecast to grow rapidly over the next 5 years as consumers demand convenient snacks with exciting sensory and textural properties. Extrusion technology has been used extensively in the production of cereal RTE snacks due to its ease of operation and ability to produce a variety of textures and shapes which appeal to consumers. Many of the existing RTE products are relatively high in sugar and salt, thus being regarded as energy dense but nutritionally poor foods. However, there exists a potential to manipulate the nutritional status of extruded RTEs by altering the digestion potentials of starch and protein, and by the incorporation of bioactive components such as dietary fibre. The review article explores some of the recent research in this field and illustrates opportunities by which the global food industry could react to consumers' requirements for healthful RTE snack products in the coming years.