Comparison of the specific mechanical energy, specific thermal energy, and functional properties of cold and hot extruded pea protein isolate.

Pea protein is a popular source of plant-based protein, though its application in meat and dairy analog products is still lacking. This is particularly true in the development of products with fatty and creamy textures. Cold denaturation may be a way to induce these types of textures in food since this is a universal phenomenon in protein that occurs due to a weakening of hydrophobic interactions at cold temperatures. This work utilizes a single screw extruder to systematically study the impacts of moisture content (50-65 %) and pH (2,4.5,8) on the outlet temperatures, specific mechanical energy, specific thermal energy, and texture of cold-extruded pea protein. It was found that at pH 2 and moistures of 60 % and greater, the temperature of the product exiting the extruder is <5.5 °C, and also produced 13.7 %-36.5 % more specific thermal energy, indicating the occurrence of cold denaturation in these products. Based on these findings, a comparison of hot and cold extrusion was conducted as a function of pH and oil content. It was found that cold extrusion imparts 43.0 %-56.2 % more mechanical energy into the protein than hot extrusion, and the cold extruded protein had higher values of Young's modulus and breaking stress. The protein extruded at low temperatures was also able to bind 32.93 % more oil than hot extruded proteins when extruded with 10 % added oil, which may aid in the formation of protein-based fat memetics for the food industry.

Physicochemical characterization of changes in pea protein as the result of cold extrusion.

Pea protein is a popular plant-based protein for mimicking textures in meat and dairy analogues which are more sustainable than their animal-based counterparts. However, precise mechanisms for generating specific textures through different processing methods are still being evaluated. This work utilizes a novel low-temperature extrusion process to selectively alter the chemical structure of pea protein. Changes in secondary structure, surface hydrophobicity, electrostatic interactions, and disulfide bonding are characterized through FTIR, ANS- probes, zeta potential, and SDS-PAGE. Extrudates are further characterized using texture parameter analysis. It was found that a linear combination of physicochemical data, generated with multiple linear regression modelling, led to reasonable estimates of the specific mechanical energy and textural properties. This work offers a new method of reactive extrusion to selectively modify interactions in pea protein using low temperature extrusion, and applications may include fatty textures, since the extrudates are found to be largely stabilized through hydrophobic interactions evaluated with surface hydrophobicity measurements.

Acceptability of locally produced ready-to-use therapeutic foods in Ethiopia, Ghana, Pakistan and India.

Successful treatment of severe acute malnutrition has been achieved with ready-to-use therapeutic food (RUTF), but only 15% of children with severe acute malnutrition receive RUTF. The objective of this study was to determine whether new formulations of RUTF produced using locally available ingredients were acceptable to young children in Ethiopia, Ghana, Pakistan and India. The local RUTFs were formulated using a linear programming tool that allows for inclusion of only local ingredients and minimizes cost. The study consisted of 4 two-arm, crossover, site-randomized food acceptability trials to test the acceptability of an alternative RUTF formula compared with the standard peanut-based RUTF containing powdered milk. Fifty children with moderate wasting in each country were enrolled in the 2-week study. Acceptability was measured by overall consumption, likeability and adverse effects reported by caregivers. Two of the four RUTFs did not include peanut, and all four used alternative dairy proteins rather than milk. The ingredient cost of all of the RUTFs was about 60% of standard RUTF. In Ethiopia, Ghana and India, the local RUTF was tolerated well without increased reports of rash, diarrhoea or vomiting. Children consumed similar amounts of local RUTF and standard RUTF and preferred them similarly as well. In Pakistan, local RUTF was consumed in similar quantities, but mothers perceived that children did not enjoy it as much as standard RUTF. Our results support the further investigation of these local RUTFs in Ethiopia, Ghana and India in equivalency trials and suggest that local RUTFs may be of lower cost.

A Method to Determine the Density of Foods using X-ray Imaging.

Density of foods is an important physical property, which depends on structural properties of food. For porous foods such as baked foods, accurate measurement of density is challenging since traditional density measurement techniques are tedious, operator-dependent and incapable of precise volume measurement of foods. To overcome such limitations, a methodology was developed using both digital radiography(DR) and computed tomography(CT) x-ray imaging to directly determine density of foods. Apparent density was determined directly from x-ray linear attenuation coefficients by scanning at 40, 60, 80 kVp on DR and 45, 55, 70 kVp on CT. The apparent density can be directly determined using CT however sample thickness is needed to determine density using DR. No significant difference (p<0.05) was observed between density obtained from traditional methods, with density determined from x-ray linear attenuation coefficients. Density determined on CT for all foods with mean 0.579 g/cm3 had a standard deviation, SD = 0.0367 g/cm3. Density determination using x-ray linear attenuation was found to be a more efficient technique giving results comparable with conventional techniques.

An Overview of The Technology Assisted Dietary Assessment Project at Purdue University.

In this paper, we describe the Technology Assisted Dietary Assessment (TADA) project at Purdue University. Dietary intake, what someone eats during the course of a day, provides valuable insights for mounting intervention programs for prevention of many chronic diseases such as obesity and cancer. Accurate methods and tools to assess food and nutrient intake are essential for research on the association between diet and health. An overview of our methods used in the TADA project is presented. Our approach includes the use of image analysis tools for identification and quantification of food that is consumed at a meal. Images obtained before and after foods are eaten are used to estimate the amount and type of food consumed.