Development and investigative studies on solar hot case food warmer for food safety at offices/institutes.

The paper presents the design, development and investigative studies into the use of a solar hot case/food warmer. The solar hot case can prove to be highly useful to the persons who carry hot food to their workplaces for lunch and eat it 4-5 h later. It can help keep food warm and infection free, by maintaining the food at an elevated temperature. The solar hot case has been developed with a total aperture area of 0.673 m2. The energy requirements for food warming have been calculated and found to be around 62 kJ in summer and 90 kJ in winter for an average lunch box of mass 0.25 kg containing 0.4 kg of food. The design of the solar hot case has been prepared on the basis of the food warming calculations to allow around ten lunch boxes to be warmed simultaneously. A computer program based on the solar radiation geometry and an ASHRAE model has been prepared to study the energy available in various months and to estimate the solar energy interception by the solar hot case. The results show that the energy absorbed by the system at an instant varies from around 300 to 1400 kJ/m2h in winter and 1000-2000 kJ/m2h in summer. Experimental in-field observations related to the temperature profiles of the developed system are also reported.

Improving rural women's health in China: cooking with clean energy.

It is well known that women bear the greatest burden of health, work time, and labor supply due to gender disparity in many developing countries. In this study, we analyze the health inequality in rural China caused by indoor air pollution from traditional energy use. Specifically, we study the effect of clean energy access on woman health outcome by exploiting a nationwide rollout of clean cooking fuel program in 2014. Based on interviews with rural women in 2014 and 2016, this study analyzes the impact of clean energy use on women's health by using the propensity score matching method with the difference-in-differences model (PSM-DID). We also analyze the heterogeneous health effects of clean energy uptake on rural women with different characteristics. The results show that clean energy applications can significantly improve the health of rural women. The positive health effects are substantial for middle-aged and older women, illiterate women, and those women lived in northeastern China. The results highlight the role of clean energy in reducing gender disparities in health inequality.

New vacuum cooking techniques with extra-virgin olive oil show a better phytochemical profile than traditional cooking methods: A foodomics study.

In this work, the major changes in extra-virgin olive oil (EVOO) composition during cooking were assessed. A foodomics approach based on both metabolomics and lipidomics was used to evaluate the impact of six different cooking techniques, three traditional and three more innovative (Crock-pot®, Roner® and Gastrovac®), and the effect of temperature and cooking time. The lipophilic and hydrophilic fractions of EVOO that underwent different cooking processes were characterized by untargeted high-resolution mass spectrometry approaches. Multivariate statistics were used to unravel the differences in chemical signatures. The different cooking methods resulted in broadly different phytochemical profiles, arising from thermally driven reactions accounting for hydrolysis, synthesis, and oxidation processes. The innovative cooking techniques marginally altered the phytochemical profile of EVOO, whereas sauteing was the cooking method determining the most distinctive profile. Conventional cooking methods (oven, pan-frying, and deep-frying) produced more oxidation products (epoxy- and hydroxy-derivatives of lipids) and markedly induced degradation processes.

The impact of emerging domestic and commercial electro-heating technologies on energy consumption and quality parameters of cooked beef.

The purpose of this study was to investigate the effects of e-Cooker® and moderate electric field (MEF) cooking on physical and chemical changes occurring during the cooking of meat. Beef muscle samples (38.86 ± 0.08 g) were cooked in saline solution (0.5% w/w NaCl) to a target temperature of 72 °C, followed by a 2 min holding time. The experimental results revealed that e-Cooker® and MEF significantly reduced the come-up time required to achieve a target temperature of 72 °C to 1.16 ± 0.02 min and 0.86 ± 0.02 min, respectively compared to 14.12 ± 0.55 min in conventional cooking. The colour and instrumental texture of cooked meat by e-Cooker® and MEF systems were not significantly different (P > 0.05) from conventionally cooked ones. Overall, the results obtained demonstrated that e-Cooker® and MEF can be used to cook meat in a shorter time and reasonably low energy input while producing a product which is comparable in quality to conventionally cooked meat.

Is oven bag really advantageous in terms of heterocyclic aromatic amines and bisphenol-A? Chicken meat perspective.

Herein, the effects of oven bag use belong to different brands on heterocyclic aromatic amine (HAA) formation and bisphenol-A (BPA) migration in cooked chicken meats (breast and leg) were investigated. Samples were also analyzed in terms of some qualitative properties (fatty acid profile, water, fat, pH, TBARS, cooking loss). Both oven bag use and meat type had an effect on qualitative properties of the samples. Total HAA amount changed between 6.53 and 42.32 ng/g, and HAA content was higher in breast meat. Total BPA content in samples cooked with oven bag ranged between non-quantified to 63.78 ng/g. Oven bag use reduced the total HAA amount at the rate of 12 - 68.82%, while it caused the BPA migration depends on the brand. However, it can be noted that the HAA and BPA levels were not at a level to pose a risk to human health in any of the samples.

Use of ohmic heating as an alternative method for cooking pasta.

BACKGROUND: In this study, the alternative method of ohmic heating (OH) was applied to investigate its potential usage in the cooking process for pasta and its comparison with the conventional method. For this purpose, OH was operated at four different voltage gradients (10, 20, 30, 40 V cm-1 ). The electrical conductivity of pasta σ (S m-1 ) was calculated for the temperature range 22-95 °C and a three-phase linear relation between σ and temperature was determined. RESULTS: According to the results, the energy consumption of the OH system and cooking time were lower than the conventional method. Energy conservation was about 73.7% at 40 V cm-1 and increased up to 90.4% (at 10 V cm-1 ) with lower voltage gradients. Total cooking time, cooking loss, water absorption, degree of gelatinization, volume uptake, energy consumption and sensorial properties were investigated. No significant differences between the results of samples cooked with the conventional method and OH at 30-40 V cm-1 were found in terms of starch gelatinization degree, volume change, water absorption, and sensorial analysis (P > 0.05). CONCLUSION: These results revealed that OH did not cause any negative effects on the quality parameters of pasta samples, and positive effects were observed on energy and time saving. © 2021 Society of Chemical Industry.

Effect of cooking temperature on cooked pasta quality and sustainability.

BACKGROUND: Everyday pasta cooking has a large environmental impact. The aims of this work were to assess the effect of cooking temperatures (TC ) that were lower than the water boiling point (TBW ) on the main chemico-physical quality parameters of two pasta shapes (i.e., ziti and spaghetti) cooked at the conventional and minimum water-to-pasta ratios, as well as their optimum cooking time (OCT), cooking energy consumption, and carbon footprint, by using a novel eco-sustainable pasta cooker. RESULTS: Once the effect of TC on OCT had been modeled in accordance with the Bigelow model, it was possible to estimate that the energy saved to heat the cooking water from ambient temperature to a lower temperature than TBW was smaller than the extra energy needed to complete the pasta cooking phase. After several cooking trials, the water uptake, cooking loss, textural properties, and thickness of the central nerve (as observed with a scanning electronic microscope) of cooked pasta were found to be independent of TC in the range of 85-98 °C. CONCLUSIONS: By using smaller amounts of water (~3 L kg-1 ) and cooking at 85 °C with the eco-sustainable pasta cooker, the energy consumption reduced from the default value of 2.8 kWh kg-1 to ~0.45 kWh kg-1 and GHG emissions to about one sixth of those resulting from the use of the average European home appliances. © 2021 Society of Chemical Industry.

Effect of high-pressure pre-soaking on texture and retrogradation properties of parboiled rice.

BACKGROUND: The poor palatability, low digestibility, and unpleasant color of parboiled rice (PR) have severely hampered its acceptance by consumers. It is hence necessary and urgent to develop a new method for producing high-quality PR. In the current study, the effect of high hydrostatic pressure (HHP) pre-soaking on the color, textural properties, and the degree of retrogradation of PR was investigated. RESULTS: With HHP from 100 to 500 MPa, the water adsorption rate increased and cooking time decreased. Parboiled rice samples presented higher lightness scores (L) and had lower color intensity (B). Compared with a control group, PR samples treated with high-pressure pre-soaking showed a reduction of hardness values from 0.69% to 32.99%, and gumminess values also decreased from 8.58% to 33.62%. The differential scanning calorimetry (DSC) results indicated that the enthalpy values of PR samples decreased after high pressure pre-soaking. The molecular structure of PR characterized by Fourier transform infrared spectrometry confirmed that HHP pre-soaking could decrease the retrogradation level. CONCLUSION: The findings outlined above suggest that the texture and retrogradation properties of PR were improved after high-pressure pre-soaking. © 2021 Society of Chemical Industry.

Comparison of physical, microstructural and antioxidative properties of pumpkin cubes cooked by conventional, vacuum cooking and sous vide methods.

BACKGROUND: Current dietary guidelines recommend five or more fruit, vegetable, and legume servings per day. Often, these products are eaten cooked, resulting in organoleptic and nutritional changes. Vacuum cooking is gaining attention as an alternative cooking technique, due to its ability to preserve or even enhance sensory and healthy properties of food. Its household application is, however, poorly explored. In this work, the effect of vacuum cooking, performed with a new patented system, was studied for the first time on pumpkin cubes and compared to sous vide and traditional steam cooking, through a multidisciplinary approach. RESULTS: All the cooking treatments damaged pumpkin microstructure, leading to cell separation and plasmolysis; vacuum cooking was the most aggressive method, as confirmed by texture softening. Vacuum cooking was also the method with less impact on pumpkin color, in relation to the largest extraction of some classes of carotenoids from the broken cells. Significant polyphenol extraction, especially of gallic acid and naringenin, was instead observed for sous vide and steamed pumpkins. The total antioxidant activity, ascribable to the effect of both carotenoids and polyphenols, resulted enhanced after cooking compared to raw one mainly for cook vide samples, followed by steamed and sous vide ones. CONCLUSIONS: Vacuum cooking, followed by sous vide, has often shown better performance than traditional steam cooking for pumpkin cubes. The implementation of sous vide and vacuum cooking at domestic level or in professional kitchens, and in the food industry, would allow the consumption of vegetables with improved nutritional and sensorial characteristics. © 2020 Society of Chemical Industry.

Effect of dry heating on egg white powder influencing water mobility and intermolecular interactions of its gels.

BACKGROUND: Dry heat processing remains the most promising and simple approach for achieving better gelling properties of spray-dried egg white powder (EWP). Water mobility and intermolecular interactions in gels derived from EWP were investigated after subjecting EWP to various dry heating times (0-21 days). RESULTS: The gel hardness and water-holding capacity significantly increased with an increase in dry heating time (P < 0.05), and both parameters were positively correlated with gel transparency. In contrast to the coarser structure of untreated EWP gel, the gel of EWP corresponding to 15 days of dry heating time had a fine-stranded and orderly network structure with smaller pores. An increase in the binding force between the gel and water was observed with an increase in dry heating time due to the formation of more 'protein-water' hydrogen bonds. Increasing the dry heating time resulted in an increase in the contribution of disulfide bonds, which in turn made a significant contribution to the rigidity of the EWP gels. By contrast, a decrease in the contribution of ionic bonds and hydrophobic interactions upon increasing the dry heating time promoted the formation of orderly networks. CONCLUSIONS: Overall, gel corresponding to EWP dry heating for 15 days had better gel properties, the highest transparency and water-holding capacity, as well as a fine-stranded and orderly network structure. These results provide more information on improvement of the gel properties of EWP through dry heat treatment. © 2020 Society of Chemical Industry.

Negligible Oleandrin Content of Hot Dogs Cooked on Nerium oleander Skewers.

INTRODUCTION: The Nerium oleander plant contains cardenolides that may cause human poisoning when ingested. A long-standing belief holds that it is possible to be poisoned by eating hot dogs or other foods cooked on Nerium oleander branch skewers. Oleandrin levels in frankfurters cooked on fresh and dry Nerium oleander skewers were measured. METHODS: Hot dogs were cooked separately on either dried or fresh oleander branch skewers using a disposable charcoal grill. The hot dogs were then frozen and transported to an analytical laboratory where oleandrin content was measured via liquid chromatography/mass spectroscopy (LC/MS). RESULTS: The oleandrin content of hot dogs cooked on dried and fresh skewers did not exceed 343 ng and 701 ng, respectively. CONCLUSION: Hot dogs cooked on Nerium oleander skewers contain a negligible amount of oleandrin with respect to that sufficient to cause human poisoning. Reports of poisonings occurring in this manner are most likely the result of an urban myth.

Optimization of roasting conditions in hydroSOStainable almonds using volatile and descriptive sensory profiles and consumer acceptance.

HydroSOStainable almonds are harvested from trees cultivated under controlled water stress by using a regulated deficit irrigation (RDI) strategy. The aim of this study was to investigate consumers' perception to select the best roasting temperature for the hydroSOStainable almonds and its correlation with volatile compounds, descriptive sensory attributes, instrumental color, and texture. Thirty-five volatile compounds were identified and the key compounds for the roasting process were 2,5-dimethylpyrazine, furfural, and trimethyl pyrazine. Pyrazines, furans and, in general, volatiles were higher in hydroSOStainable almonds than in control. Instrumental color and trained panel showed that almonds roasted at 190 °C presented intense color and burnt notes in both irrigation treatments, while almonds roasted at 150 °C were under-roasted. Principal component analysis (PCA) grouped together the samples of the same irrigation treatment, but separated samples roasted at different temperatures. Partial least square regression (PLS) results indicated that consumers overall liking was positively linked to specific volatiles (alkanes, alcohols, aldehydes, and furans) and sensory attributes (sweetness, roasted, almond ID, nutty, hardness, and crispiness), but, negatively correlated with pyrazines, bitterness, astringency, woody, and burnt flavor notes. Penalty analysis showed that almonds roasted at 150 and 190 °C were penalized due to low roasted aroma and soft almonds, and over-roasted samples with too intense color and burn notes, respectively. While no penalization being found for almonds roasted at 170 °C. Overall, roasting at 170 °C for 10 min in a convective oven were the optimum conditions for roasting Vairo almonds. PRACTICAL APPLICATION: This research describes the link between physicochemical and sensory analysis of roasted almonds giving evidence about possible sensory quality markers. Besides, it provides valuable information for the food industry to produce roasted almonds that meet consumer demands and for the agricultural sector by encouraging reduction of irrigation water consumption by almond trees.

Effectiveness of Gas and Chimney Biomass Stoves for Reducing Household Air Pollution Pregnancy Exposure in Guatemala: Sociodemographic Effect Modifiers.

Household air pollution (HAP) due to solid fuel use during pregnancy is associated with adverse birth outcomes. The real-life effectiveness of clean cooking interventions has been disappointing overall yet variable, but the sociodemographic determinants are not well described. We measured personal 24-h PM2.5 (particulate matter <2.5 µm in aerodynamic diameter) thrice in pregnant women (n = 218) gravimetrically with Teflon filter, impactor, and personal pump setups. To estimate the effectiveness of owning chimney and liquefied petroleum gas (LPG) stoves (i.e., proportion of PM2.5 exposure that would be prevented) and to predict subject-specific typical exposures, we used linear mixed-effects models with log (PM2.5) as dependent variable and random intercept for subject. Median (IQR) personal PM2.5 in µg/m3 was 148 (90-249) for open fire, 78 (51-125) for chimney stove, and 55 (34-79) for LPG stoves. Adjusted effectiveness of LPG stoves was greater in women with ≥6 years of education (49% (95% CI: 34, 60)) versus <6 years (26% (95% CI: 5, 42)). In contrast, chimney stove adjusted effectiveness was greater in women with <6 years of education (50% (95% CI: 38, 60)), rural residence (46% (95% CI: 34, 55)) and lowest SES (socio-economic status) quartile (59% (95% CI: 45, 70)) than ≥6 years education (16% (95% CI: 22, 43)), urban (23% (95% CI: -164, 42)) and highest SES quartile (-44% (95% CI: -183, 27)), respectively. A minority of LPG stove owners (12%) and no chimney owner had typical exposure below World Health Organization Air Quality guidelines (35 µg/m3). Although having a cleaner stove alone typically does not lower exposure enough to protect health, understanding sociodemographic determinants of effectiveness may lead to better targeting, implementation, and adoption of interventions.

Effects of sourdough on improving the textural characteristics of microwave-steamed cake: A perspective from dielectric properties and water distribution.

A sourdough combined with microwave heating method was adopted to make steamed cake (SSC), the dough yield, fermentation time and additive amount of sourdough were optimized by Response Surface Methodology (RSM) to obtain microwave-steamed cake (MSSC) with high-quality attributes and then the potential mechanism of sourdough on the improvement of the MSSC texture was investigated. The addition of sourdough with the optimized parameters could greatly improve the specific volume, porosity, hardness, and chewiness of MSSC, which was mainly related to changes in dielectric properties and water distribution. The results of dielectric properties confirmed that sourdough increased the dielectric properties of the system during microwave heating, affecting the microwave heating characteristics. And the changes of water states and distribution by T2 relaxation analysis showed that sourdough restricted water mobility during heating and facilitated the retention of water trapped in MSSC. Additionally, the scanning electron microscopy (SEM) images indicated that sourdough weakened the gluten network structure, and triggered a looser and smoother microstructure. PRACTICAL APPLICATION: Steamed cake (SSC) is one of the most popular fermented foods in China, while its commercial development is greatly limited by the drawbacks of traditional steam heating. In recent years, the applications of microwave heating and sourdough in cereal-based foods processing have gained more and more interest. However, there is little information about the application of sourdough combined with microwave heating in SSC production. This study revealed that sourdough addition increased the specific volume, porosity, texture, and consumer preference of MSSC, providing a natural, high-efficiency, and easy-to-operate means for the fabrication of high-quality fermented foods.

Comparison of Liquefied Petroleum Gas Cookstoves and Wood Cooking Fires on PM2.5 Trends in Brick Workers' Homes in Nepal.

Prior studies document a high prevalence of respiratory symptoms among brick workers in Nepal, which may be partially caused by non-occupational exposure to fine particulate matter (PM2.5) from cooking. In this study, we compared PM2.5 levels and 24 h trends in brick workers' homes that used wood or liquefied petroleum gas (LPG) cooking fuel. PM2.5 filter-based and real-time nephelometer data were collected for approximately 24 h in homes and outdoors. PM2.5 was significantly associated with fuel type and location (p < 0.0001). Pairwise comparisons found significant differences between gas, indoor (geometric mean (GM): 79.32 µg/m3), and wood, indoor (GM: 541.14 µg/m3; p = 0.0002), and between wood, indoor, and outdoor (GM: 48.38 µg/m3; p = 0.0006) but not between gas, indoor, and outdoor (p = 0.56). For wood fuel homes, exposure peaks coincided with mealtimes. For LPG fuel homes, indoor levels may be explained by infiltration of ambient air pollution. In both wood and LPG fuel homes, PM2.5 levels exceeded the 24 h limit (25.0 µg/m3) proposed by the World Health Organization. Our findings suggest that increasing the adoption of LPG cookstoves and decreasing ambient air pollution in the Kathmandu valley will significantly lower daily PM2.5 exposures of brick workers and their families.

Autoclaving and extrusion improve the functional properties and chemical composition of black bean carbohydrate extracts.

Common beans (Phaseolus vulgaris L.) are rich in starch with a high content of amylose, which is associated with the production of retrograded and pregelatinized starch through thermal treatments. The purpose of this study was to evaluate the composition, morphology, thermal, functional, and physicochemical properties of carbohydrate extracts (CE) obtained from autoclaved (100 and 121 °C) and extruded (90, 105, and 120 °C) black beans. After evaluation of the functional properties, the CE from autoclaved beans at 100 °C for 30 min and 121 °C for 15 min 2×, and extruded beans at 120 °C and 10 rpm, were selected to continue the remaining analysis. Autoclaving treatments at 100 °C for 30 min and 121 °C for 15 min 2× showed a reduction of resistant starch by 14.4% and 26.6%, respectively, compared to dehulled raw bean CE. Meanwhile, extrusion showed a reduction in resistant starch of 54.2%. Autoclaving and extrusion treatments also decreased the dietary fiber content. Extrusion reduced almost entirely the content of α-galactooligosaccharides, in comparison to dehulled raw bean CE. The results showed differences in color and granule morphology. The onset, peak, and conclusion temperatures, transition temperature range, and enthalpy of autoclaved and extruded bean CE were lower than dehulled raw bean CE. The CE from autoclaved and extruded beans contain retrograded and pregelatinized starch, which could be incorporated in food products as a thickening agent for puddings, sauces, creams, or dairy products. PRACTICAL APPLICATION: Thermally treated black bean carbohydrate extracts are rich in starch, fiber, and protein. Because these extracts are already cooked, they can be added to products that do not require a thermal process such as puddings, sauces, creams, or dairy products, acting as a thickening agent.

Effect of low-temperature vacuum heating on physicochemical properties of sturgeon (Acipenser gueldenstaedti) fillets.

BACKGROUND: Sturgeon is popular for its nutritious value and its taste. However, sturgeon fillets are traditionally heated in 100 °C boiling water, resulting in unfavorable taste and with a negative effect on the quality. This study considered the effect of combinations of vacuum and low-temperature treatments (LTVH groups) on sturgeon fillets compared with the traditional heat treatment (TC groups). RESULTS: The results show that the LTVH groups had lower cooking-loss rates. All LTVH fillets were changed to a white color, and appeared 'done', as did the TC fillets. The LTVH and TC methods gave rise to significant differences in texture: the springiness of the LTVH groups decreased with heating time, and decreased rapidly in the TC groups (P < 0.05); hardness and chewiness increased with time and temperature in the LTVH groups, but decreased in the TC groups. More compact and denser gaps were observed in LTVH70 groups and TC groups. Less protein and lipid oxidation was evident in LTVH groups, including more myofibril protein solubility; there was less protein aggregation, fewer thiobarbituric acid reactive substance, and Schiff base. CONCLUSION: Vacuum and low-temperature treated sturgeon fillets can be served as a good alternative. This treatment caused slight tissue damage and less proteolysis and lipid oxidation, which is beneficial for the quality of aquatic products.