Selected Applications of Water Activity Management in the Food Industry

ABSTRACTCommon salt (NaCl) is frequently used by the food industry to add flavor and to act as a humectant in order to reduce the water content of a food product. The improved health awareness of consumers is leading to a demand for food products with reduced salt content; thus, manufacturers require alternative water activity-reducing agents which elicit the same general effects as NaCl. Two examples include KCl and glycerol. These agents lower the water activity of a food matrix and also contribute to limit the growth of the microbiota, including foodborne pathogens. Little is currently known about how foodborne pathogens respond to these water activity-lowering agents. Here we examined the response ofSalmonella entericaserovar Typhimurium 4/74 to NaCl, KCl, and glycerol at three time points, using a constant water activity level, compared with the response of a control inoculum. All conditions induced the upregulation of gluconate metabolic genes after 6 h of exposure. Bacteria exposed to NaCl and KCl demonstrated the upregulation of the osmoprotective transporter mechanisms encoded by theproP,proU, andosmU(STM1491 to STM1494) genes. Glycerol exposure elicited the downregulation of these osmoadaptive mechanisms but stimulated an increase in lipopolysaccharide and membrane protein-associated genes after 1 h. The most extensive changes in gene expression occurred following exposure to KCl. Because many of these genes were of unknown function, further characterization may identify KCl-specific adaptive processes that are not stimulated by NaCl. This study shows that the response ofS. Typhimurium to different humectants does not simply reflect reduced water activity and likely involves systems that are linked to specific humectants.

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Validated Empirical Models Describing the Combined Effect of Water Activity and pH on the Heat Resistance of Spores of a Psychrotolerant Bacillus cereus Strain in Broth and Béchamel Sauce

Journal of Food Protection ◽

10.4315/0362-028x.jfp-11-041 ◽

2011 ◽

Vol 74 (10) ◽

pp. 1662-1669 ◽

Cited By ~ 7

Author(s):

S. SAMAPUNDO ◽

M. HEYNDRICKX ◽

R. XHAFERI ◽

F. DEVLIEGHERE

Keyword(s):

Heat Resistance ◽

Bacillus Cereus ◽

Water Activity ◽

Food Industry ◽

Polynomial Function ◽

Polynomial Equation ◽

Combined Effect ◽

Major Objective ◽

Validation Data ◽

Bias Factor

The major objective of this study was to evaluate and model the combined effect of the water activity (aw) and pH of the heating menstrum on the heat resistance of spores of a psychrotolerant Bacillus cereus strain isolated from béchamel sauce. Two models, a quadratic polynomial equation and a reparameterized function, were assessed for their ability to describe the combined influence of aw and pH on the D85°C-values of the B. cereus isolate in tryptone soy broth. The performance of the models was validated by challenging the models with data independently collected in broth and béchamel sauce. Both models were found to adequately describe the validation data obtained in broth. However, it was determined that in béchamel sauce the predictions of the polynomial function not only showed bias (bias factor = 1.156) but were also fail-dangerous, as they deviated from the validation data by 17.2%. The reparameterized function was determined to be a good predictor of the D85°C-values in béchamel sauce as it showed no bias (bias factor = 1.033) and its predictions differed by only 7.9% from the validation data. The reparameterized function can be used to provide estimates of the minimum processing conditions required to achieve desired levels of spore inactivation within the aw and pH ranges studied and to determine the potential changes in heat resistance of B. cereus spores when aw and pH are changed, for example, during product reformulation. As validation of heat resistance models is rarely performed, let alone in actual food products, the models evaluated and validated in this study (in particular the reparameterized function) are of immediate relevance to the food industry.

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Shelf-Life Evaluation of Ingredient Combinations and Technologies for Use in Pet Food Formulations

Animals ◽

10.3390/ani12020152 ◽

2022 ◽

Vol 12 (2) ◽

pp. 152

Author(s):

Madison P. Wagoner ◽

Marc R. Presume ◽

Moses E. Chilenje ◽

Gerardo A. Abascal-Ponciano ◽

Jorge L. Sandoval ◽

...

Keyword(s):

Lipid Oxidation ◽

Shelf Life ◽

Water Activity ◽

Technology Use ◽

Food Industry ◽

Pet Food ◽

Surface Color ◽

Life Evaluation ◽

Vacuum Package ◽

Wooden Breast

Poultry co-product chicken frames (CF) and wooden breast (WB) along with ingredient technology use may bring enhanced value to the pet food industry. Therefore, the current study focused on evaluating CF and WB combinations along with sodium alginate and encapsulated calcium lactate pentahydrate (ALGIN) inclusion within a fresh pet food formulation under simulated shelf-life conditions. Fresh chicken frames (CF) and boneless-skinless wooden breast (WB) were ground and allocated randomly to one of ten treatment combinations with either 0.5 or 1.0% added ALGIN. Ground treatments were placed into a form and fill vacuum package and stored using a reach-in refrigerated case for 21 days. Packages were evaluated for instrumental surface color, lipid oxidation, water activity, and pH on days 1, 3, 7, 14 and 21 of the display. Packages of pet food were lighter, less red, and more yellow (p < 0.05) with increasing percentages of CF regardless of ALGIN inclusion, whereas pH was greater (p < 0.05) and lipid oxidation was less (p < 0.05) with increasing percentage of WB. Water activity increased (p < 0.05) when WB and ALGIN inclusion increased. The current results suggest that the use of ALGIN in a poultry co-product pet food formulation can improve shelf-life characteristics such as surface color and lipid oxidation in fresh pet food.

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Characterization of Bioactive Compounds in Fruit and Vegetable Bagasse

JOURNAL OF BIOENGINEERING AND TECHNOLOGY APPLIED TO HEALTH ◽

10.34178/jbth.v4i2.161 ◽

2021 ◽

Vol 4 (2) ◽

pp. 58-62

Author(s):

Fernanda dos Santos Cardoso ◽

Ingrid Lessa Leal ◽

Tatiana Barreto Rocha Nery

Keyword(s):

Water Activity ◽

Bioactive Compounds ◽

Food Waste ◽

Food Industry ◽

Phenolic Content ◽

Sustainable Use ◽

Fruit And Vegetable ◽

Flavonoid Content ◽

By Products

The use of agro-industrial residues is presented in food waste. The processing of them is an opportunity for the development of by-products, as well as the aggregation of lost value, and the sustainable use of these residues. The study aimed to characterize the bioactive compounds in grape, carrot, cocoa, and banana skins from the processing of juice, banana chips, and chocolate. The analyzed samples showed good moisture, satisfactory water activity value, with the highest flavonoid content in the grape sample (1.679 mg EQ/g) and the highest phenolic content in the cocoa epicarp sample (1.367 mg EAG/g). In this way, we verified the viability of using food peels in the food industry, enabling the use of waste generated.

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Where’s the fat? Freeze-fracture analysis of ingredient interactions in food systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146084 ◽

1993 ◽

Vol 51 ◽

pp. 48-49

Author(s):

Jean Fincher

Keyword(s):

Lipid Droplets ◽

Food Systems ◽

Food Industry ◽

Freeze Fracture ◽

Food Science ◽

Complex Interactions ◽

Fat Reduction ◽

Important Trend ◽

Conventional Foods ◽

Whipped Cream

An important trend in the food industry today is reduction in the amount of fat in manufactured foods. Often fat reduction is accomplished by replacing part of the natural fat with carbohydrates which serve to bind water and increase viscosity. It is in understanding the roles of these two major components of food, fats and carbohydrates, that freeze-fracture is so important. It is well known that conventional fixation procedures are inadequate for many food products, in particular, foods with carbohydrates as a predominant structural feature. For some food science applications the advantages of freeze-fracture preparation procedures include not only the avoidance of chemical fixatives, but also the opportunity to control the temperature of the sample just prior to rapid freezing.In conventional foods freeze-fracture has been used most successfully in analysis of milk and milk products. Milk gels depend on interactions between lipid droplets and proteins. Whipped emulsions, either whipped cream or ice cream, involve complex interactions between lipid, protein, air cell surfaces, and added emulsifiers.

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