Oscar A. Pike

Sensory, Mechanical, and Microscopic Evaluation of Staling in Low-Protein and Gluten-Free Breads

ABSTRACT Staling over a 120-hr period was compared in a gluten-free rice bread, a low-protein starch bread, and two gluten-containing breads (standard wheat and added-protein wheat) using quantitative descriptive analysis (QDA), critical stress values obtained by mechanical compression testing, and scanning electron microscopy (SEM). The gluten-free rice bread had the highest QDA scores for both moistness and overall freshness, whereas the low-protein starch bread had the lowest scores for both attributes. Differences in critical stress values over the 120-hr period demonstrated that the gluten-free rice bread had the greatest resistance to mechanical collapse, indicating the least structural damage, whereas the low-protein starch bread had the least resistance to mechanical collapse. Both wheat breads had QDA moistness and freshness scores, and critical stress values that ranged between the gluten-free rice and low-protein starch breads. SEM showed the formulation containing rice, egg and milk proteins, ...

Storage, preparation, and usage of fortified food aid among Guatemalan, Ugandan, and Malawian beneficiaries: a field study report.

Background An important consideration in determining the ability of fortified food-aid commodities to meet the nutritional needs of beneficiaries is the manner in which commodities are utilized and prepared and the degree to which micronutrient losses occur during handling and cooking by the beneficiaries. Objective A field study was conducted in Uganda, Malawi, and Guatemala to obtain data on storage, preparation, and usage of fortified blended foods provided by the US Agency for International Development. Methods Interview and observational data on the use of corn-soy blend, cornmeal, soy-fortified cornmeal, soy-fortified bulgur, and fortified vegetable oil were collected from more than 100 households and two wet-feeding sites (where food is prepared and served by staff on-site) in 32 villages. Results Storage practices by beneficiaries appeared to be appropriate, and all commodities observed were free from off-flavors and odors. Cooking water was typically obtained from boreholes or open wells with a pH range of 4.7 to 7.7. Food preparation usually took place in covered areas with the use of an aluminum or clay pot over a wood-fueled fire. Thin or thick porridges were the most common dishes prepared from cereal-based products, with concentration ranges of 10% to 31% (wt/wt) in water. Cooking times for porridges ranged from 5 to 53 minutes, with a mean of 26 minutes. Tortillas and beverages were other preparations commonly observed in Guatemala. Vegetable oil was typically used for pan frying. Conclusions Cooking fuel could be saved and nutritional quality probably improved if relief agencies emphasized shorter cooking times. These data can be used to simulate preparation methods in the laboratory for assessment of the nutritional impact of cooking.

Sensory and Nutritional Quality of Split Peas (Pisum Sativum) Stored up to 34 Y in Residential Storage

The sensory and nutritional quality of split peas stored up to 34 y was determined. Nine samples of split peas representing 5 retail brands packaged in Nr 10 cans and stored at room temperature were obtained from donors. Duplicate cans of a fresh sample of split peas were purchased as controls. Can head space oxygen ranged from 0.255% to 20.1%. Water activity of the raw split peas ranged from 0.41 to 0.56. The green color of the raw split peas decreased over time as shown by increasing CIE a* values. Flavor, appearance, texture, and overall liking hedonic scores (9-point scale) of split-pea soup made from each sample ranged from 3.7 to 6.7 and decreased over time. Hedonic scores for appearance were correlated with the decrease in raw product green color (r(2)= 0.65). Hedonic scores for soup texture declined over time, which corresponded with increasing hardness of the cooked peas as measured by a TA.XT2 texture analyzer. All samples were judged to be acceptable in an emergency situation by over 75% of sensory panelists. Available thiamin was significantly lower in older samples while riboflavin remained unchanged. The results indicate that split pea quality declines over time, but the product maintains sufficient sensory acceptance to be considered for potential use in emergency storage and other applications where minimal stock rotation is a common practice.

The isolation and identification of Pantoea dispersa strain JFS as a non-pathogenic surrogate for Salmonella Typhimurium phage type 42 in flour

Salmonella is a common pathogen which has been the cause of foodborne illness outbreaks implicating a variety of commodities, including low-moisture foods such as flour. Salmonella costs more than any other pathogen in the United States in terms of health care expenses and time of lost work. Heat treatment can be used to reduce Salmonella and other pathogens in flour to safe levels. However, in low-moisture foods, process times must be increased to achieve adequate lethality, possibly resulting in changes in the flours functionality such as changes in the gluten quality, vitamin content, and the level of starch gelatinization. There is a need to determine the minimal heat treatment required to achieve desired lethality in flour and other low-moisture foods, with the goal of retaining the flours functionality. Currently there is no published data about a nonpathogenic bacterial surrogate for Salmonella in flour. In this study, a surrogate, which closely matches the thermal death rate of Salmonella in flour, has been isolated. The surrogate was identified following an evaluation of thermal death curves of ten different strains of bacteria isolated from heat-treated flour and two nonpathogenic surrogates used in other commodities. Flour samples were inoculated with Salmonella or one of the twelve bacterial isolates, and then subjected to heat (70, 75, and 80 °C) for 12-60 min. The heat tolerance for each organism was determined by plating out at least four different time points for each temperature and comparing the death curve to those from Salmonella. The death curve from Pantoea dispersa was not statistically different (p<0.05) than the death curve of Salmonella. This strain of P. dispersa (strain JFS) can be used as a conservative, slightly more heat resistant, surrogate for Salmonella. It can be used to verify the combination of heat and time necessary to kill Salmonella in flour using a commercial heat-treatment process.

Sensory and nutritional quality of white rice after residential storage for up to 30 years

Abstract Rice is a staple food that may be packaged for long-term storage to ameliorate unpredictable circumstances such as crop failures and natural disasters. The sensory and nutritional quality of 18 samples of long grain white rice (11 regular, 7 parboiled) packaged in cans stored up to 30 years at ambient temperature in residential locations was evaluated. Hedonic scores for overall liking ranged from 5.6 to 6.6 (9-point scale) and all samples regardless of age scored above 5, “neither like nor dislike”. All but one 30-year parboiled sample were considered acceptable for everyday use by greater than 50% of panelists, and for emergency use by over 88% of panelists. Thiamin concentrations ranged from 0.5 to 3.6 µg/g. Although vitamin stability appears to be limited, rice retains much of its sensory quality over time and the presence of minerals and other stable macronutrients may justify its inclusion in a long-term food storage regimen.

Folate Stability in Folic Acid Enriched Corn Masa Flour, Tortillas, and Tortilla Chips over the Expected Shelf Life

Neural tube defects occur at higher rates in Hispanic populations in the United States. Such populations would benefit from folic acid fortification of corn masa flour (CMF). This study evaluated folate stability in fortified CMFs and tortillas and tortilla chips made therefrom. There was no significant loss of folate during the six-month shelf life of fortified tortilla CMF and tortilla chip CMF. There was a 13% loss (P < 0.05) of folate during tortilla baking and no loss during tortilla chip frying. Both tortillas and tortilla chips showed significant folate losses over the two-month shelf life for these products, with a 17% loss in fortified tortillas and a 9% loss in tortilla chips. Folate in fortified CMFs, tortillas, and tortilla chips is relatively stable and comparable to the stability of folate in wheat flour and breads.

Microbial and chemical safety of non-commercially packaged water stored for emergency use.

Water storage is one of the most important components of emergency preparedness. Potable water is needed for ensuring the survival and well-being of disaster victims. Consumers may store water in previously used beverage or other food-grade containers for emergency use; however, this practice poses potential safety risks. Water stored in various containers for emergency purposes in residences within the state of Utah was tested for various contaminants. Of 240 samples, seven contained coliforms and 14 samples had free chlorine levels over the Environmental Protection Agency (EPA) 4 parts per million limit. There was a negative correlation between chlorine levels and age of water. The probability that a container had free chlorine present decreased by 4% for each month of storage, suggesting the importance of preventing subsequent contamination of water during storage and use. Water in clear polyethylene terephthalate plastic soda bottles (n=16), even when stored for >18 months, did not exceed 0.3 parts per billion (ppb) antimony, a level significantly lower than the EPA limit of 6.0 ppb antimony. These results support the practice of utilizing previously used containers, when properly cleaned and chlorinated, for emergency water storage.