Evaporative light scattering mass detection for high-performance liquid chromatographic analysis of sucrose polyester blends in cooking oils

A high-performance liquid chromatographic method is described to determine the sucrose polyester (SPE) content in seven blends of cooking oils. Four gel-permeation chromatography (GPC) columns were used in series with an evaporative light scattering mass detector to separate the SPE from the acylglycerols in the final chromatogram. The SPE fraction was collected off the GPC column and injected onto a reverse-phase C-18 column for quantitation with sucrose octaacetate as an internal standard and a gradient of nonaqueous solvents as mobile phase. The chromatograms were interference-free, with only two sharp peaks appearing. The standards were linear from 500 to 5000 μg/mL with a correlation coefficient of r=0.999. The mean percent recovery (n=9) and standard deviation were 102±6.7. The detector could detect amounts as low as 5 μg SPE.     

Cooking personas: Goal-directed design requirements in the kitchen

Technology to assist people in the kitchen has become a major research topic as technology becomes more ubiquitous in the home. Research is being carried out in numerous areas to assist with cooking, from solving difficulties in the kitchen to more recently enhancing already good experiences related to cooking. To design solutions that are not only usable, but useful in all related aspects of cooking, we must get a good understanding of the needs of the user. It is important that real needs are identified, so that products or systems designed are adopted and are sustainable. There are various methods that researchers and designers use to gain user insights and there is much debate on different approaches and their effectiveness. Whilst there have been a number of ethnographic style studies in people's homes, there has been little in the way of understanding user goals in the kitchen which could lead to more effective design solutions. In this paper, we present goal-directed research of cooking needs in Singapore. We produce three primary design personas and three secondary personas, describing their goals and needs and where they can be helped through technology. An online survey was carried out to validate our personas, comparing our qualitative and quantitative findings. We provide a general holistic overview of kitchen requirements for these personas, whether in helping correct problems or enhancing positive experiences and how these needs can be connected. The user requirements provided can help guide researchers and help designers produce more meaningful, complete and acceptable technology solutions in the kitchen.     

烹饪工艺与营养专业校内经营教学模式的构建与实践——以重庆旅游职业学院为例

烹饪工艺与营养专业的校内经营是通过学院提供校园餐厅,在课堂内完成专业培养方案的教学任务,组织学生进入校园餐厅顶岗实训,形成教学经营一体化校内经营运行模式。文章阐述了校内经营教学模式的基本思路、校内餐厅的要求和管理,总结了校内经营模式运行过程中出现的问题,并针对如何进一步完善校内经营模式提出新思路。     

Real-time estimation of slowest heating point temperature and residual cooking time by coupling multipoint temperature measurement and mathematical modelling: Application to meat cooking automation

In this work, an innovative procedure for real-time heat transfer modelling and dimensional change estimation during meat cooking was presented. By using a multipoint temperature probe, a punctual calculation of slowest heating point (SHP) temperature was obtained at each time from the radial temperature distribution inside the product. Experimental temperature data from the multipoint probe was combined with a mathematical algorithm previously validated to perform a real-time estimation of SHP temperature and residual cooking time on the basis of the data stored at each instant. The developed procedure and algorithm were validated by cooking pork loin and roast beef samples at 180 and 200 °C both under natural and forced convection regimes. Real-time predicted cooking time and SHP endpoint temperature values were very close to those experimentally obtained: at the 85% of the cooking process, the maximum percentage errors for SHP endpoint temperature and cooking time prediction were 1.72 and 1.67%, respectively. In addition, SHP location inside the meat samples was also obtained at each time instant and used to estimate dimensional changes during cooking: calculated final characteristic dimensions were very similar to those experimentally obtained for all cooking trials. The developed approach could be useful for the automatic cooking operations planning in food-service with microbial safety assurance.     

Improvement of tenderness and water holding capacity of spiced beef by the application of ultrasound during cooking

The aim of this study was to assess the effects of power ultrasound‐assisted (0, 400, 600, 800 and 1000 W, frequency of 20 kHz) cooking (80, 100, 120 min) on spiced beef. The results showed that power ultrasound could significantly increase the salt content (P < 0.05). For water holding capacity, the ultrasonic treatment could significantly reduce the pressure loss and free water content while improving the immobilised water content (P < 0.05). And ultrasonic treatment improved hardness compared with control (P < 0.05). However, the effects on the springiness, the chewiness and the resilience of the spiced beef were not significant (P > 0.05). As for microstructure, the myofibrils of beef were ruptured by ultrasonic treatment along with the Z‐lines leading to the muscle swelling. The results indicated that the application of ultrasound during cooking could effectively promote the penetration of salt, improve the water holding capacity and ameliorate the tenderness of spiced beef.     

Multimedia recipe reading: Predicting learning outcomes and diagnosing cooking interest using eye-tracking measures

This study aimed to explore the relationships between students' visual behaviors and learning outcomes, and between visual behaviors and prior cooking interest in multimedia recipe learning. An eye-tracking experiment, including pretest, recall test, and retention test, was conducted with a sample of 29 volunteer hospitality majors in Taiwan. The multimedia recipe included a static page showing the ingredients in a text-and-picture representation and a dynamic page showing the knife skills in a text-and-video representation. Total reading time, total fixation duration, number of fixations and inter-scanning count were used to explore the students' visual attention distributions among the different representation elements and their visual strategies for learning the recipe. The results showed that all students paid more visual attention to the text than to the picture information for the static recipe, and paid more visual attention to the video than to the text on the dynamic page. In addition, the visual attention paid to the text on the dynamic page was negatively correlated with the retention of the episodic knowledge of knife skills. In contrast, the visual attention paid to the text on the static ingredient page was positively correlated with students' prior cooking interest. Finally, the inter-scanning count between text and video on the dynamic page was the best index to negatively predict students' learning retention. Total fixation duration on the text information on the static page was the best index to positively predict students' prior cooking interest. Future studies and applications are discussed.     

Water sorption and cooking time of red kidney beans (Phaseolus vulgaris L.): part I – Effect of freezing and drying conditions on water sorption and cooking time

Water sorption and cooking time of kidney beans were determined. The beans were manually harvested at 19.2 ± 0.1% moisture content and stored at ?20 and ?10 °C for about half a year. The beans were further dried at 30, 40 and 50 °C inside a thin‐layer drier for 7.5 h or under room conditions for 4 week. The freezing storage temperature before the beans were dried did not influence their cooking time and water sorption. The saturated kernel volumes decreased approximately 7% after drying. The beans decreased their sphericity during water sorption and had a larger swelling ratio in the thickness direction than in other directions. Lower initial moisture content, especially with a higher drying temperature, decreased water sorptivity and resulted in higher percentage of uncooked kernels if the beans were not soaked before cooking. However, there was no relationship between initial moisture content and uncooked percentage if the beans were soaked before cooking. High drying temperature resulted in hard‐to‐cook (HTC) phenomenon.     

Model-based multi-objective optimization of beef roasting

A validated mathematical model has been used to perform multi-objective optimization of beef roasting, considering the minimization of both cooking time and weight loss. Simulations were performed using irregular geometrics models of beef semitendinosus muscle and constant oven temperature. Minimum temperature of 72 °C at the coldest point was imposed as a constraint. From model results a compromise situation was encountered, since no operative condition lead simultaneously to optimal values of both objectives, i.e., an increase in oven temperature leads to a decrease in cooking time, between −0.25 and −0.325 min/°C, and an increase in weight loss, between 0.175 and 0.275%/°C. In this sense, not one, but a set of optimal solutions was found in the Pareto sense. Experimental cooking tests were performed, which are in good agreement with model simulations. Furthermore, energy consumption for each optimal solution obtained in the optimization problem was estimated, being lower using low oven temperatures.     

Meat quality and cooking attributes of thawed pork with different low field NMR T(21)

A relationship of low field NMR T(2) components to meat quality and cooking attributes of pork was investigated. Longissimus muscle was removed from 23 pig carcasses at 24h postmortem for meat quality measurements and cooking test. Frozen samples were classified into three groups by LF-NMR T(21) of thawed samples: A (<40ms), B (40-44ms) and C (>44ms). There were significant differences (P<0.05) in pH, lightness (L* value) and pressing loss among the three groups. Cooking time to attain 70°C was slightly lower in group C than the other groups. Shear force value of cooked samples was not affected by T(21). The component T(21) correlated (P<0.05) with L* value, muscle pH and pressing loss, while L* value correlated (P<0.05) with thawing loss and muscle pH. Therefore, combined LF-NMR and color measurements could be a good way to differentiate water holding capacity of pork.