Volume 12, Issue 2 -

Effect of interactions between Jerusalem artichoke flour (JF), wheat flour (WF) and sugar (S) on the texture properties of cookies was investigated. JF was the most influential component on the dough and cookies, possibly due to inulin in JF. To develop an optimum formulation using mixture design, the constraint values for the quality indices were: hardness (12 N), adhesiveness (10 mJ), and cohesiveness (0.27) of dough, and maximum force of cookie (73 N). Optimum values of WF, JF and S in the mixture were found to be 151.89 g, 55.33 g and 87.78 g, respectively, with a desirability of 0.943. Two experimental cookie formulas, similar to the optimal formula, were tested for their sensory properties and resulted in highly acceptable scores. As baking time increased, the browning and antioxidant activity of all cookies increased; however, the browning and antioxidant activity of samples containing JF was significantly higher than the others.

The occurrence of turbidity is a frequently observed phenomenon in beet sugar manufacturing, particularly in thick juice. The presence of small dispersed turbidity-causing particles can have a direct impact on the consumer’s perceivable quality of white sugar containing products. Therefore, this work aims to characterize those turbidity-causing particles and elucidate the mechanism of their formation. Samples from various European beet sugar plants were collected during different sugar production periods. The turbidity of white sugar is found to be mainly related to small calcium oxalate particles (0.45–1 µm). Their occurrence is obviously related to the presence of calcium and oxalate. However, the analysis presented documents that beyond the levels of these ions, other factors like storage time, the change of environment due to microbiological processes as well as simple processing steps have a profound effect on turbidity levels. The results confirm that also at an industrial scale calcium oxalate dihydrate precipitates from concentrated sucrose solutions despite the fact that calcium oxalate monohydrate is the most stable form. In summary our analysis of turbidity at an industrial scale marks a starting point for any further turbidity reduction approach.

Bambara groundnut and cowpea legume seeds with a very high nutritive value are widely produced and consumed in most sub-Saharan African countries. The aim of this work which is part of a large study was to compare the potential of bambara groundnut and cowpea varieties of flour as basic raw material for the preparation of a widely legume-based food product known as koki . Toward this objective standard methods were used to analyze some morphological, microstructural and thermal properties of these legume flours along with their respective isolated starches and proteins. In general, thermal transition of proteins has slow enthalpy energy of less than 1 J g −1 . The gelatinization temperature and the enthalpy of gelatinization of starches in the flours were lower as compared to those of isolated starches, suggesting here an interaction of starch with other components during the gelatinization process. All starches are of A-type and the degree of crystallinity of bambara starch was higher than that of cowpea starch. Scanning electronic microscopy revealed that starch granules of North cowpea (NC), West cowpea (WC) and White bambara groundnut (WB) were polygonal while that of Black bambara (BB) starch were spherical in shape. The flowability characteristic of the flour and starch shows that bambara flour with small particle size (~90%<100 µm) had a high compressibility (47.38–43.16%) as compared to cowpea flour (32.18–30.24%). NC and VB starch granules have a size between 10 and 35 µm while WC and BB are too small (6–15 µm). NC and WB starch granule sizes are between 10 and 35 µm while WC and BB’s sizes are too small (6–15 µm). Bambara groundnut and cowpea flour along with their respective isolated starches and proteins therefore appears to be a valuable raw material which may be useful for the preparation of many food products.

The freezing tolerance of the strawberries related to the application of various pretreatment methods combined with air blast (AB) or cryomechanical (CM) freezing was investigated during 24 weeks of frozen storage. Osmotic pretreatments with lemon juice (LJ) solution and crystallized sucrose (CS) exerted significant protective effects on color stability of frozen-thawed strawberries. As compared with no pretreatment, the combined pretreatment using sodium alginate (SA) or low methoxyl pectin (LMP) vacuum-infusion (VI) and subsequent calcium dipping for frozen strawberries reduced firmness loss by 11.5–34.2% and reduced drip loss by 84.6–91.7% depending on specific VI solutions and calcium concentration, while SA or LMP VI alone showed no significant improvement in the retention of texture. CM freezing not only provoked significant reductions in overall freezing time and moisture loss compared to AB freezing, but also resulted in minimizing color and texture instability of frozen strawberries when combined with the three-step pretreatment process.

This paper presents the comparative analysis of a traditional raw milk dispenser and an innovative prototype based on nanofluid technology. The traditional raw milk dispenser consists of an off-the-shelf upright air-cooled refrigerator sold on the market, whereas the innovative prototype presents a tank equipped with a serpentine tube jacket operated with Al 2 O 3 –ethylene glycol aqueous solution nanofluid. The systems are experimentally analysed in the ambient temperature range of 19–35°C to evaluate the energy performance and the temperature control of the milk tank. The innovative prototype is demonstrated to be superior from the point of view of both energy saving and food safety. In fact, the innovative prototype exhibits a 63–70% energy saving with respect to the traditional one. Furthermore, the prototype distributor is able to reach the “safe” temperature of 4°C in about half of the time required by traditional system and it keeps the milk always in the “safe” temperature range 2–3°C, while the traditional distributor displays locally milk temperature higher than 4°C.

The objective of this study was to investigate different drying methods (oven-drying, vacuum-drying, and freeze-drying) applied to cooked mussels meat and the resulting rehydration and water-holding capacity. Drying curves were obtained using an online weighting system that allows continuous monitoring of sample weight during processing. The influence of the processing temperature on the drying rates and on the properties of dehydrated samples was assessed. In the studied conditions, freeze-drying presented higher drying rates and less structure alterations compared to the other drying methods investigated. The equilibrium rehydration capacity of oven-dried and vacuum-dried mussels was about 37 % lower than rehydration capacity of freeze-dried samples for the rehydration performed at 20 °C and about 21 % lower for rehydration performed at 80 °C.

In the present study, soaking and blanching soybean were studied by time-domain nuclear magnetic resonance (TD-NMR) relaxometry and magnetic resonance imaging (MRI). Four proton fractions with different mobilities were observed in dried, soaked and blanched soybean samples, which reflects macromolecule, oil and water in different microenvironment of soybean. The proton distribution of soybean was significantly changed during soaking process. According to the result of MRI, water may initially penetrated into soybean from its radicle and micropyle. In terms of water distribution, the optimum soaking time for soybean was appeared to be 8 h. Blanching also significantly changed the proton distribution of soybean. During blanching, all four proton fractions became more mobile, and the accumulation of extracellular water was observed due to the partial destruction of cell/membrane integrity. The heat-induced variations of cotyledon tissues structure mainly occurred in the first 30 min, which implied blanching process should last at least for 30 min.

Mathematical models including mass and energy conservation were developed in order to predict the outlet particles temperature and moisture. As the inlet air temperature increased, the outlet particles temperature increased as well and the outlet particles moisture decreased quickly. The outlet particles temperature and moisture changed a little as a function of the speed of rotation at the low inlet air temperature, while the outlet particles temperature and moisture increased very apparently with the speed of rotation increased at the high inlet air temperature. The error of the simulation results compared to the experimental data showed good accuracy for particles temperature and moisture content. The mathematical model performs well to predict the outlet particles temperature and moisture content.

Functional properties of Bambara bean protein concentrates (BPCs), as a function of extraction pH and NaCl concentration, were investigated. The results showed that protein content of the concentrates ranged between 69.27% and 74.40%. The addition of NaCl during protein extraction favourably affected water solubility index particularly at pH 10–11. Moreover, the maximum water absorption capacity (4.28 g/g) and oil-holding capacity (OHC) (2.50 g/g) were recorded at extraction pH 11 and in the absence of NaCl. It was also noticed that protein extraction at pH 8–10 was not recommended for applications where high OHC is required. BPCs presenting high emulsifying activity were prepared at NaCl concentration of 0.5 M and pH 7, and at pH 11 without NaCl. Finally, foaming ability (FA) increased with NaCl concentration, and the maximum FA was recorded at pH 7 (114%).

This study investigated effects of pretreatments on rehydration characteristics of solar-dried carrot slices. Blanching at 55, 65 and 75°C for 45 minutes and osmotic dewatering in 5%, 10% and 15% salt solutions for 5 h were used as pretreatments. Rehydration capacity of the dried carrots was determined by soaking 20 g sample in hot water at 95°C for 10 min and rehydration kinetics was carried out by soaking 5 g samples at 75, 85 and 95°C. All the treatment conditions separately and in combination influenced the rehydration characteristics of the carrot slices. High values of rehydration capacity and low lixiviated soluble solids, which indicates better quality, were obtained for samples treated at the lower blanching temperature. Similarly the lower salt concentration resulted in higher rehydration capacity and lower lixiviated soluble solids. The interaction of the lower level of both pretreatments produced higher rehydration capacity and lower soluble solid losses. A first-order kinetic model was used to describe the rehydration kinetics. A better rehydration performance was observed for the samples subjected to the lower levels of pretreatments and rehydration conditions.