Subjective and objective assessments of the degree of cooking of potatoes heated by different methods

Standard potato slices were heated for various periods of time by three different methods: boiling water, steam under pressure, and a microwave oven. After heating, the internal temperature was measured together with textural characteristics to assess the degree of cooking, using both a taste panel and an Instron 1140 machine.
It was found that for a given method of heating the taste panel score is related to the instrumental measurements of rupture load and rupture energy. It was also found that the degree of cooking of a potato does not depend solely on the internal temperature reached, but is also dependent on the heating method and particularly on the rate of heating.     

NEED FOR ACHIEVEMENT IN NEGRO, WHITE, AND PUERTO RICAN CHILDREN.

COMPARED N ACH OF NEGRO, WHITE, AND PUERTO RICAN 5TH AND 7TH GRADERS IN LOW SOCIOECONOMIC AREAS OF A LARGE NEW ENGLAND CITY. THE N ACH TESTS CONSISTED OF 6 TOPIC SENTENCES ABOUT WHICH SS WROTE STORIES. F TESTS OF N ACH SCORES REVEALED NO SIGNIFICANT DIFFERENCES. THESE RESULTS CONTRAST WITH THE AUTHOR'S A.D. MINGIONE'S (SEE39:4) PREVIOUS STUDY IN WHICH WHITE CHILDREN HAD HIGHER N ACH SCORES THAN NEGRO CHILDREN AND 7TH GRADERS SCORED HIGHER THAN 5TH GRADERS. THERE WERE MORE WORDS PER STORY, GREATER VARIETY OF STORY THEMES, AND MORE STORIES CONCERNING FEMALES WRITTEN BY BOTH BOYS AND GIRLS THAN IN THE PREVIOUS STUDY, WHEN THE STORIES WERE WRITTEN IN RESPONSE TO LINE DRAWINGS OF PEOPLE. SCHOOL GRADES AND GROUP INTELLIGENCE TEST SCORES DID NOT CORRELATE WITH N ACH SCORES IN THIS STUDY. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PHYSICAL AND SENSORY PROPERTIES OF MEATSTICK PRODUCTS AS AFFECTED BY FORMULATION AND DRYING: SENSORY-INSTRUMENTAL RELATIONSHIPS

Shelf‐stable meats are of interest to industry and are important in military ration development. Stability is commonly achieved through control of pH and water activity. However, reduction in moisture as a means to lower a_w can significantly affect texture. Other ingredients, such as fat, can also potentially affect texture and possibly mitigate hardening due to lowered moisture. Meatsticks dried to three water activities, 0.88, 0.90, and 0.92, each from batters at three fat levels, 14, 17, and 21%, were produced, yielding products varying in both moisture and fat content. Products were subjected to mechanical and sensory testing and image and color analysis. Meatstick modulus, shear force, L* value, and percent of area of cut surfaces covered by separated fat were correlated with sensory assessments of interior hardness, hardness with skin, color, and visual fat, respectively. These parameters were significantly influenced by composition, particularly fat and protein contents and fat‐protein interaction.     

A MODEL OF FOOD SPREADABILITY FROM FLUID MECHANICS

Subjective spreadability was predicted through understanding of psychophysical mechanisms involved during the back and forth spreading action of foods on crackers. Transient complex Theology of food products is incorporated into mass and momentum balances used to model the spreading action. Furthermore, because the consumer is in contact with the food product through a knife, it is assumed that the inverse of the torque needed to generate the deformation is assessed as spreadability. Torque is assumed to be equal to the shear stress on the knife multiplied by the distance the knife traueled across the cracker. Because this distance is constant, the final form for the psychophysical model is:

Using magnitude estimation, subjective spreadability scores ranged from 0.13 for marshmallow cream to 5.23 for squeeze margarine. When these scores were plotted versus the model on log-log coordinates, the best slope was 0.85 with a correlation coefficient of 0.95. The results strongly support the assumption that shear stresses generated on the knife are assessed as spreadability by the consumer.     

Evaluation of the incubated plate count test for pasteurized milk

Factors were examined which may influence bacterial psychrotroph counts obtained by the European Community's directed preincubation test for pasteurized milk. Studies to determine the best protocol for sampling milk indicated that the least counting error was obtained by taking at least five consecutive samples of milk. Increasing the number of replicate plates or making subsamples did not decrease counting error. When milk samples from five commercial dairies were examined over an 11 month period there was a significant difference (p < 0·001) in counts obtained over the period, but this did not seem to be a seasonal effect. The counts between dairies were not significantly different nor was the position in the pasteurization run from which the samples were taken significant. The proportion of samples which failed the test standard was 9.7% over the period. The bacterial flora isolated from plate count agar were identified; Gram­negative rods were the most common isolates. The spiral plater system was compared with the pour plate method in the preincubation test and results were found to be in close agreement, suggesting that the spiral plater could be used to improve the current official methods. Varying the time and temperature of sample preincubation was found to give significantly different results in plate counts. This suggested that preincubation conditons were critical and that variation in conditions even within the specified ranges of the test could significantly alter the bacterial psychrotroph counts obtained. Because of these results, the validity of the statutory test was questioned.     

THERMAL INACTIVATION KENETICS of PECTINESTERASE EXTRACTED FROM ORANGES

A study was carried out on the kinetics of thermal inactivation of pectines terase (PE), extracted from the pulp of Valencia and Navel oranges. Moreover, the influence of intrinsic factors on the kinetics of Navel orange PE was investigated. In a citric acid buffer, at a pH of 3.7 and 4.2, the enzyme was more thermostable as compared to water. However, at pH 3.2 an increased inactivation and an increased temperature sensitivity of the rate constant was observed. Ca²⁺-ions also enhanced the inactivation, whereas the temperature sensitivity of the rate constant decreased. In presence of sucrose, a diminished inactivation of PE was observed, and addition of sucrose only slightly influenced the activation energy.     

Moving House,Creating Home: Exploring Residential Mobility

This paper begins with a review of the residential mobility literature that arose out of housing and planning policy aimed at decreasing the negative effects of urban transience. The literature identified the range of factors influencing residential mobility, but Rossi's (1955) claim that mobility was a 'natural' outcome of life stage changes became the basis for the majority of this work. Most of this literature arose out of quantitative research approaches but writers drew attention to the inability of these approaches to capture the increasing complexity of family life and residential mobility. Drawing on data from the Christchurch, New Zealand, house and home study, this study argues that the qualitative ethnographic method used provides a more holistic approach to, and understanding of, the events and issues which influence household mobility over time. Within this context, the paper presents excerpts from interview data framed as ontological narratives and related stories embedded in social and economic contexts. Some of the themes identified are those of identity, home and place attachment, change and social differentiation, and the impact of gender relations on mobility decisions and experiences. These findings, like those in previous literature, are relevant to housing and planning policy making given the increasing diversity of residential developments and issues of access to social, financial and environmental resources. Understanding how individuals and families establish relationships between themselves and the places in which they live is important given increasingly divided and differentiated experiences of contemporary urban life.     

Thermodynamic Properties of Cerium Oxalate and Cerium Oxide

Differential scanning calorimetry and thermogravimetry were used to determine the thermodynamic properties of cerium oxalate. Hydrated cerium oxalate was found to contain 13 molecules of water and decomposed producing three thermal events corresponding to the loss of adsorbed water, water of hydration, and decomposition of anhydrous cerium oxalate to cerium oxide. Anhydrous cerium oxalate obeyed first-order reaction kinetics where -In(1-a)=kt. Reaction rates, heat capacities, and equations for the heat capacities are given.     

SENSORY AND MECHANICAL ATTRIBUTES OF GEL TEXTURE

Eighteen experienced judges evaluated the texture of gels varying in gelatin concentration (22-45 g/L) in terms of firmness by oral and manual shear and compression, cohesiveness, and extent of breakdown in the mouth. Manual compression and biting with the front teeth discriminated well across gel concentrations. All sensory measures except extent of breakdown increased with gelatin concentration. Instron (IUTM) measurements showed that increasing gelatin concentration resulted in an increase in maximum force and force/deformation, but had little effect on deformation at yield and rupture or in elasticity and cohesiveness. Results from mechanical measurements varied with the type of force applied (compression, shear or puncture), the loading rate (50 or 200 mm/min), and the extent of deformation attained (40–90%). The highest discrimination across gel concentrations was achieved with shear force at a rate of 200 mm/min and at greater deformations. Sensory responses correlated most highly with the following IUTM measurements: (1) Compression forces at yield and at deformations of 70 and 85% at the higher crosshead speed; (2) Compression forces below the yield point at the lower crosshead speed; and (3) Shear forces measured at maximum deformation (90%) at 200 mm/min.