Children's acceptability profiles for biscuits with different fiber content.

Due to the widespread rejection by children of products with high-fiber content, new approaches to meet the dietary recommendations on fiber intake are necessary. To understand which sensory properties influence this rejection, children's acceptability was examined in high-fiber biscuits and drivers of liking were identified. One hundred and ten Spanish children (6-12 years old) evaluated the overall liking of eight commercial biscuits with variable fiber content and stated their preference. To study the drivers of liking, the samples were characterized through a quantitative descriptive analysis, the determination of the moisture and water activity as well as the instrumental evaluation of texture with a texture analyzer. It was suggested that the addition of fiber in biscuits reduced children's liking ratings. High-fiber samples were sensory and instrumentally described as harder, crispier, and more chewing than the samples with medium and low fiber content. The main sensory driver of liking identified in this study was the soft texture. Despite their hard texture, high- and medium-fiber samples were chosen as the preferred ones for 14% of the children that participated when they included chocolate taste. Drivers of disliking identified in this study were related to the addition of fruit as a filling or as dehydrated pieces. This knowledge about children's acceptability of high-fiber products might be of interest for the food industry with the aim of developing well-accepted products that supply nutritional deficiencies associated with the fiber intake.

High-pressure pretreatment in albacore (Thunnus alalunga) for reducing freeze-driven weight losses with minimal quality changes.

BACKGROUND: This research evaluates the application of high-pressure processing (HPP) before freezing to reduce weight loss related to thawing and cooking of frozen albacore steaks (Thunnus alalunga) with a minimal impact on fish quality (color, texture, soluble protein, lipid oxidation). Albacore steaks were HPP pretreated (200, 250, and 300 MPa for 0, 2, 4 and 6 min), frozen (-20 °C, 5 m s-1 ), thawed (4 °C; 24 h), and then analyzed. RESULTS: At lower pressures (200 MPa) there was a clear effect of pressurization time on most of the fish quality parameters tested (thawing loss, L* value, b* value, ΔE, adhesiveness, springiness, salt-soluble protein content), whereas at higher pressures (300 MPa) similar changes took place independently of the pressurization time. High-pressure processing had no impact on lipid oxidation . A pressure of 200 MPa applied for 6 min decreased thawing, cooking, and total weight losses (53.7%, 55.4%, and 51.0% lower than the frozen control, respectively) although it led to noticeable changes in color. A pressure of 200 MPa applied for 2 min decreased thawing, cooking, and total weight losses by 23.2%, 44.0% and 33.7% with respect to the frozen control, respectively, with only minor changes in color. CONCLUSION: High-pressure processing pretreatment could be a promising tool for reducing weight loss in frozen fish when HPP conditions are properly selected. A pressure of 200 MPa applied for 2 min could be a good compromise treatment, cutting thawing and cooking losses in albacore, and reducing HPP-mediated color alterations and the related possible consumer rejection. © 2020 Society of Chemical Industry.

Specific and sensitive ELISA for measurement of IgE-binding variations of milk allergen ß-lactoglobulin in processed foods.

Immunochemical detection of food allergens is usually based on the use of polyclonal or monoclonal immunoglobulins G (IgG) antibodies. However, due to differences in epitopes recognition between IgG and IgE, an epitope modification during food processing can potentially alter allergenicity and detection in such different way. For that reason, the use of traditional immunological methods to anticipate or study the protein allergenicity is not recommended. The objective of this work was to develop a standardized competitive ELISA, based on recombinant IgE antibodies to ß-lactoglobulin (ß-lg), to reveal and to measure changes in ß-lg immunoreactivity provoked by technological processes in foods containing this milk protein. As a result, a sensitive immunochemical method (Limit of Detection, LOD < 0.2 µg mL-1) has been developed for ß-lg recognition. Also, this technique has been confirmed to detect modifications in ß-lg-IgE binding after food processing (thermal treatment) in a similar way to those results obtained with allergic patients in previous works. Consequently, data obtained with this assay could be used as a preliminary test to predict in vitro ß-lg allergenic behavior in allergenicity studies in processed foods.

Inactivation of Bacillus subtilis spores by combined pulsed light and thermal treatments.

The combined effect of pulsed light (PL) and heat processing was evaluated on the inactivation of Bacillus subtilis spores. Those processes were applied separately and the time between both treatments was modified to evaluate whether the effect of the first treatment is maintained for a long time. B. subtilis spores subjected to sublethal pre-treatments were more sensitive to subsequent treatments (PL or thermal treatments) than untreated spores. Heating followed by PL was the most effective combination in reducing B. subtilis counts. Bacterial spores remained sensitized to subsequent treatment for at least 24 h of storage in water, whatever the temperature was (4 or 30°C). Sensitivity of B. subtilis cells to PL or heat processing increased after germination in a nutrient broth, being equally sensitive from 3 to 24 h. Vegetative cells maintained their enhanced sensitivity to subsequent processing after spore germination. The results of this work demonstrate that the combination of heating and PL treatment is a promising preservation method for microbial inactivation.

Olive oil pilot-production assisted by pulsed electric field: impact on extraction yield, chemical parameters and sensory properties.

The impact of the use of pulsed electric field (PEF) technology on Arroniz olive oil production in terms of extraction yield and chemical and sensory quality has been studied at pilot scale in an industrial oil mill. The application of a PEF treatment (2 kV/cm; 11.25 kJ/kg) to the olive paste significantly increased the extraction yield by 13.3%, with respect to a control. Furthermore, olive oil obtained by PEF showed total phenolic content, total phytosterols and total tocopherols significantly higher than control (11.5%, 9.9% and 15.0%, respectively). The use of PEF had no negative effects on general chemical and sensory characteristics of the olive oil, maintaining the highest quality according to EU legal standards (EVOO; extra virgin olive oil). Therefore, PEF could be an appropriate technology to improve olive oil yield and produce EVOO enriched in human-health-related compounds, such as polyphenols, phytosterols and tocopherols.

The effect of High Pressure and High Temperature processing on carotenoids and chlorophylls content in some vegetables.

The effect of High Pressure (HP) and High Pressure High Temperature (HPHT) processing on carotenoid and chlorophyll content of six vegetables was evaluated. In general, carotenoid content was not significantly influenced by HP or HPHT treatments (625 MPa; 5 min; 20, 70 and 117 °C). Regarding chlorophylls, HP treatment caused no degradation or slight increases, while HPHT processes degraded both chlorophylls. Chlorophyll b was more stable than chlorophyll a at 70 °C, but both of them were highly degraded at 117 °C. HPHT treatment at 117 °C provided products with a good retention of carotenoids and colour in the case of red vegetables. Even though the carotenoids also remained in the green vegetables, their chlorophylls and therefore their colour were so affected that milder temperatures need to be applied. As an industrial scale equipment was used, results will be useful for future industrial implementation of this technology.

Influence of ß-lactoglobulin and ß-casein on Listeria innocua inactivation by pulsed light.

The effect of ß-lactoglobulin and ß-casein on the pulsed light (PL) inactivation of Listeria innocua was evaluated. For low protein concentrations (ß-lactoglobulin and ß-casein up to 10 mg/mL), the lowest fluences applied (0.2 J/cm(2)) induced more than 7 Log reductions in cell counts. However, higher fluences were needed to induce similar reduction in L. innocua counts when this bacterium was suspended in solutions of higher protein concentration. The fluence required to induce similar microbial inactivation was lower in ß-casein than in ß-lactoglobulin solutions. For all protein solutions, the inactivation curves followed first order kinetics. The specific inactivation rate for L. innocua inactivation in protein solutions depended on the quantity of light transmitted in the range 230-290 nm by protein solutions. This work shows that PL technology could be used for the decontamination of high protein content solutions like whey or even higher protein concentration solutions.

Cell volume changes during rapid temperature shifts.

The effect of a rapid temperature increase on the volume of different types of cells was investigated. Experiments were carried out using continuous microscopic image analysis. Volume variation of yeast cells, yeast spheroplasts and human leukaemia cells was measured during the transient phase after a thermal shift. The thermal shift was found to induce rapid increase in cell volume for cells lacking a cell wall (yeast spheroplasts and human leukaemia cells). This increase in cell volume is assumed to be a main cause of the heat shock-induced cell death. A theoretical mechanistic model that explains the behaviour of these cells is finally proposed.