The Effects of Okara Ratio and Particle Size on the Physical Properties and Consumer Acceptance of Tofu.

Okara, the solid byproduct of soymilk production, poses a sustainability concern, despite being rich in fiber and other healthful compounds. In this study, the physical properties of tofu made from soymilk fortified with differing levels of okara-either whole or fine (<180 µm)-and made with the traditional coagulant nigari were examined. The yield increased linearly with the okara concentration with values of 18.2-29.5% compared to 14.5% for the control. The initial moisture in the fortified samples was higher than the control (79.69-82.78% versus 76.78%), and both the expressible moisture and total moisture after compression were also greater in the fortified samples. With a few exceptions, the texture parameters did not differ between samples. Dynamic rheology showed that all samples had G' > G″. The storage moduli increased at different rates during each gelling step, with G' before and after gelling increasing with the fortification level, and was greater for the samples with fine particles than with whole particles. Consumer sensory panels using the hedonic scale showed traditional tofu had a slightly higher acceptability, but the panelists indicated they would be more willing to purchase okara-fortified tofu because of the health and sustainability benefits it might have. Thus, tofu could be produced with added okara with predictable but not profound changes in its physical properties.

Sensory Analysis of a Processed Food Intended for Vitamin A Supplementation.

Provitamin A and pre-formed vitamin A compounds are essential micronutrients for humans. However, vitamin A deficiency (VAD) affects the health status of nearly 50% of populations in Southeast Asia and sub-Saharan Africa and is especially pronounced in preschool children and pregnant women. The objective of this research was to determine an acceptable flavor/ingredient combination to produce a palatable food product that incorporates sweet potatoes, peanut paste, and chickpeas. We sought to determine the acceptability of the three product formulations and to determine the influence of demographic data on ratings for the sensory attributes of each sample. To address VAD issues, three formulations of a product incorporating sweet potato puree (to increase ß-carotene content), pure peanut butter (to provide fat for ß-carotene absorption), and chickpeas (to provide a complete protein source), were developed: (1) an unflavored control, and two formulations with added natural seasonings: (2) curry-flavored, and (3) pumpkin spice-flavored. Sensory analysis of the three products showed that the curry-flavored product received the highest acceptability in terms of overall liking, flavor, texture, and appearance (p < 0.001). Since the demographic effect was not statistically significant (p > 0.05), it is highly likely that the curry-flavored product can be implemented in other countries or areas with high acceptability.

The Effect of the Ultra-High-Pressure Homogenization of Protein Encapsulants on the Survivability of Probiotic Cultures after Spray Drying.

Interest in probiotic foods and ingredients is increasing as consumers become more aware of their potential health benefits. The production of these products often involves the use of dry culture powders, and the techniques used to produce such powders often suffer from significant losses of viable cells during drying or require the use of expensive drying technologies with limited throughput (e.g., freeze drying). In this study, the authors examined whether culture survivability during spray drying could be increased via the treatment of two common protein encapsulants with ultra-high-pressure homogenization (UHPH). Lactobacillus plantarum NRRL B-1927 (also known as ATCC 10241), a probiotic strain, was suspended in either soy protein isolate (SPI) or whey protein isolate (WPI) which had been either treated with UHPH at 150 Mpa or left untreated as a control. The suspensions were then dried using either concurrent-flow spray drying (CCSD), mixed-flow spray drying (MFSD) or freeze drying (FD) and evaluated for cell survivability, particle size, moisture content and water activity. In all cases, UHPH resulted in equal or greater survivability among spray dried cultures, showed reductions in particle size measures and, except for one marginal case (CCFD SPI), significantly reduced the moisture content of the dried powders. The combination of these findings strongly suggests that UHPH could allow probiotic powder manufacturers to replace freeze drying with spray drying while maintaining or increasing product quality.

Inactivation of vegetative cells by continuous high-pressure processing: new insights on the contribution of thermal effects and release device.

UNLABELLED: Dynamic or continuous high-pressure processing of fluid foods has drawn significant interest as a microbial reduction process in the past decade, and many attempts have been made to better understand the mechanisms involved in that reduction. This study was intended to provide insight into the contributions of thermal effects and differences in pressure release components in the inactivation of 2 vegetative pathogen analogs--the Gram-positive Listeria innocua and the Gram-negative Escherichia coli. Fluids containing microbial loads of 10(8) or greater were subjected to continuous high-pressure processing at 200 to 210 MPa. Without active cooling of the release components, all fluids experienced a temperature rise in excess of 70 °C, thus occluding any pressure-related effects for all release components. Active cooling of the valve bodies of the 2 valve-style release components (a conical disruption valve and a micrometering valve) allowed the temperature rise to be abated enough to isolate the effects unique to a given valve. In Tryptic soy broth trials, the mean inactivation levels of E. coli between valves were similar--5.16 log and 5.33 log for the micrometering and conical disruption valves, respectively. When repeated with L. innocua, a similar inactivation level was observed in the conical disruption valve (5.1 log) but not the micrometering valve (3.02). Listeria innocua trials were also repeated using fluid whole milk, which showed a lower levels of inactivation--2.04 log for the micrometering valve and 2.51 log for the conical valve. PRACTICAL APPLICATIONS: This paper compares some of the most common pressure release components used in continuous high-pressure processing and attempts to isolate the contributions of thermal effects from those of pressure and shear. This information is important to those seeking to compare and evaluate the effectiveness of a proposed set of process parameters for microbial inactivation. Further, the ability to reduce the extreme nature of the temperature rise has the potential to expand the use of process into more temperature sensitive products.