Source: PENNSYLVANIA STATE UNIVERSITY submitted to
IMPROVEMENT OF THERMAL AND ALTERNATIVE PROCESSES FOR FOODS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0185805
Grant No.
(N/A)
Project No.
PEN03777
Proposal No.
(N/A)
Multistate No.
NC-136
Program Code
(N/A)
Project Start Date
Oct 1, 2000
Project End Date
Sep 30, 2005
Grant Year
(N/A)
Project Director
Anantheswaran, R. C.
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802
Performing Department
FOOD SCIENCE
Non Technical Summary
There is a need to improve quality and retain nutritional value for processed food products, and to develop novel methods of processing food products. An engineering study of thermal and alternative processes used to manufacture food products will be conducted.
Animal Health Component
(N/A)
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
50150102020100%
Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
5010 - Food;

Field Of Science
2020 - Engineering;
Goals / Objectives
To develop and verify methods for measurement and prediction of engineering and biochemcial properties of foods as needed in process design and analysis, and product development. To measure and model process dependent kinetic parameters which affect food quality and safety attributes. To identify and describe transport mechanisms occurring in food processes. To develop mathematical models for analysis, design, and improvement of food processes.
Project Methods
Heat and mass transfer occurring during microwave heating of foods will be studied. The effect of composition on dielectric properties of foods will be investigated. Technologies to implement modified atmosphere and modified humidity packaging for fresh produce will be developed.

Progress 10/01/00 to 09/30/05

Outputs
Microwave based instruments provide on-line measurement of the bulk sample due to the relatively long wavelength. Characterization of Guided Microwave Spectrometry was conducted. Coaxial cables did not have a significant effect on the spectrum and the characteristic dip in the passband region was due to antenna resonance. The antenna affected the number of the resonances present in the spectrum, the frequency location and the amplitude of the resonances. GMS system has both a lower and upper amplitude limit beyond which its resolution decreases significantly. This can be resolved by using a signal attenuator and a smaller sensor body. Dielectric properties of starch slurries (0-20%) with high-methoxy pectin at levels ranging from 0-2%, were measured at diffent temperatures by using a network analyzer and an open-ended coaxial cable in order to study gelatinization. The frequency of measurement of dielectric properties did not have much effect on the dielectric constant, but the loss factor of the starch slurries increased with frequency. Increasing starch concentration led to a significant decrease in the dielectric constant and increase in the loss factor. Addition of pectin led to a significant decrease in the dielectric constant and an increase in the loss factor, when compared to a starch slurry with no added pectin. A new approach for investigating moisture diffusion through heterogeneous food systems was developed. This was used to understand diffusion in chocolate-based coatings, containing fat, sugar, cocoa powder and lecithin. The predicted diffusion coefficient through a coating containing fat and varying amounts of sugar and cocoa powder were determined by incorporating the diffusivity data from the time-lag experiments and the partition coefficient obtained from the moisture sorption isotherms. The effect of sugar, cocoa powder, emulsifier, fat type, and storage environment on the water vapor permeability of a chocolate-based coating was studied. The vane method was used to measure the yield stress of dark chocolate. Dark chocolate did not exhibit a peak startup stress during controlled shear rate (as observed with other food products). The controlled-stress resulted in a gradual change in the curvature for the displacement versus shear stress, and hence an actual point of yield could not be determined. The effect of different ratios of sucrose:corn syrup:moisture on the Tg as measured by differential scanning calorimetry and dynamic mechanical thermal analysis was studied. A direct correlation exists between DSC glass transition temperatures (enthalpy) and DMTA glass transition temperatures (structure). Both DSC and DMTA Tg data were modeled using the Gordon and Taylor equation. The effect of growth temperatures on the inactivation of L. monocytogenes in UHT whole milk by high-pressure processing is being currently investigated. A patent was obtained for the experimental setup that was developed for measuring the oxygen transmission rate of micro-perforated films. Work is being continued to develop a technique to measure the water vapor transmission ratios of micro-perforated films.

Impacts
On-line measurement of food composition plays an important role in ensuring good quality control during processing operations. Dielectric-property based sensors offer a non-invasive technique to measure food properties. Moisture diffusion in food materials is of fundamental importance to many food processes and stydying diffusion helps to control food quality. The ingredients and processing conditions have a profound influence on physical characteristics of hard candy and product quality. Hard candy manufacturing is very empirical and no systematic research has been published on the relationship between ingredients and glass transition temperatures. L. monocytogenes is a Gram positive foodborne pathogen which causes the rare, but potentially fatal, disease listeriosis. Listeriosis is commonly associated with consumption of raw milk, soft cheeses, hot dogs and deli meats. Alternative processes such as high-pressure processing can result in safer processes to manufacture fresh cheeses which cannot be thermally processed. There are a variety of factors that affect the sensitivity of microorganisms to high-pressure procerssing, and these need to be better understood in order to develop a safe high-pressure process. In order to develop modified atmosphere and modified humidity packaging technologies to improve the shelf-life of fruits and vegetables, microperforated film technology is being currently used, Film permeabilities to oxygen and water vapor are essential to design appropriate packaging systems.

Publications

  • Shetty, A. 2004. Oil migration in fat-based confectionery. M.S. Thesis, Pennsylvania State University, University Park, PA. 123 pp


Progress 01/01/04 to 12/31/04

Outputs
The vane method was used to measure the yield stress of dark chocolate using controlled shear rate and controlled shear stress measurements. The yield stress using the controlled-rate method was determined from the peak startup stress and for controlled shear stress using the single tangent method. Dark chocolate did not exhibit a peak startup stress during controlled shear rate (as observed with other food products). The controlled-stress resulted in a gradual change in the curvature for the displacement versus shear stress, and hence an actual point of yield could not be determined. The single tangent method results in an yield stress that is highly dependent on when the test was terminated. The data was linearized using various data transformations, and the onset, midpoint, endpoint yield stress values were determined from controlled shear stress measurements. It might be more appropriate for the yield stress of chocolate to be characterized as a range, with the midpoint being reported as the yield stress value. Hard candy manufacturing is very empirical and no systematic research has been published on the relationship between ingredients and glass transition temperatures (Tg). The effect of different ratios of sucrose:corn syrup:moisture on the Tg as measured by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) was studied. The effect of moisture on a 92:8 fructose:corn syrup formulation was determined by measuring both the DSC and DMTA Tg. The samples were collected at different temperatures throughout the cooking process to ensure homogeneity of the samples. Comparison was made between the fructose:corn syrup:moisture Tg to the sucrose:corn syrup:moisture glass transition temperatures as measured by both the DSC and DMTA instruments. A direct correlation exists between DSC glass transition temperatures (enthalpy) and DMTA glass transition temperatures (structure). Both DSC and DMTA Tg data were modeled using the Gordon and Taylor equation. The DSC sucrose:corn syrup data was modeled using the Couchman and Karasz (solids, moisture) and the Kalichevsky and Blanshard (sucrose, corn syrup, moisture) equations. The Tg at all ratios of sucrose:corn syrup mixtures at a given moisture content can be determined using the Gordon and Taylor k value, the weight fractions of sucrose and corn syrup, and the Tg of sucrose and corn syrup at the desired moisture level.

Impacts
Understanding of the yield stress of chocolate will assist in control of chocolate flow during pumping and metering operations during manufacturing. The results of our study on characterization thermal and mechanical detremination of glass transition in sacahhride mixtures have implications for hard candy manufacturing.

Publications

  • Ziegler, G. R., Shetty, A., and Anantheswaran, R. C. 2004. Nut oil migration through chocolate. The Manufacturing Confectioner. 84(9):118-126.
  • Ghosh, V., Duda, J. L., Ziegler, G. R. and Anantheswaran, R. C. 2004. Diffusion of moisture through chocolate-flavored confectionery coatings. Transactions of IChemE 82(C1):35-43.
  • Ghosh, V., Ziegler, G. R. and Anantheswaran, R. C. 2004. Moisture migration through chocolate-flavored confectionery coatings. J. Food Engineering 66:177-186.
  • Baker, B. S. 2004. Measurement of yield stress in chocolate using the vane method. M.S. Thesis, The Pennsylvania State University, University Park, PA. 191pp.
  • Kiefer, B. A. 2004. Thermal and mechanical determination of glass transition temperature in saccharide mixture. M.S. Thesis. The Pennsylvania State University, University Park, PA. 68pp.
  • Motwani, T., Seetharaman, K. and Anantheswaran, R. C. 2004. Dielectric properties of starch solutions as influenced by pectin and gelatinization. Paper presented at the 2004 Annual Meeting of IFT, Las Vegas, NV, July 12-16 (Published as abstract # 17G-4).
  • Ziegler, G. R., Shetty, A., and Anantheswaran, R. C. 2004. Oil migration in fat based confectionery. Paper presented at the 2004 Annual Meeting of IFT, Las Vegas, NV, July 12-16 (Published as abstract # 17F-20).
  • Shah, N. G., Zambre, S., Venkatesh, K. V. and Anantheswaran, R. C. 2004. Ozone gas exposure to extend shelf-life of tomatoes in hot-humid region. Paper presented at the 2004 Annual Meeting of IFT, Las Vegas, NV, July 12-16 (Published as abstract # 99B-17).


Progress 01/01/03 to 12/31/03

Outputs
A new approach for investigating moisture diffusion through heterogeneous food systems was developed. This approach was used to understand diffusion in chocolate-based coatings, containing fat, sugar, cocoa powder and lecithin (emulsifier). The diffusion coefficient of moisture diffusing through fat was obtained by using time-lag experiments. Moisture sorption isotherms for fat, sugar and cocoa powder was obtained by equilibrating them over saturated salt solutions. Experiments were conducted with coatings containing different amounts of cocoa powder to validate the model. For coatings containing just oil and cocoa powder, the diffusion of moisture in the dispersed phase, i.e. cocoa powder, occurred through the cocoa powder particle. When lecithin was added, the water molecules diffused through the cocoa powder particles as well as along their surfaces. The effect of sugar, cocoa powder, emulsifier, fat type, and storage environment on the water vapor permeability (WVP) of a chocolate-based coating was studied. In addition, optical microscope images of cocoa powder and SEM images of the structure of two different coatings were obtained. A coating containing more than 20% cocoa powder (w/w) increased the WVP; a coating containing 60% sugar decreased the WVP. There was an increase in the WVP with an increase in the absolute value of the relative humidity across the film. This increase was caused due to swelling of the cocoa powder particles that changed the structure of the coatings. The WVP of fat films decreased with increase in the solid fat content (SFC) when the SFC was below 80%, increasing the SFC over 80% increased the WVP. A mechanism for moisture migration through chocolate coatings was proposed. Selection of appropriate packaging material for a modified atmosphere packaging system of mushrooms requires information of respiration rates of fresh mushrooms. The respiration rates of fresh mushrooms (Agaricus bisporus) at 12oC under different atmospheric conditions were measured by flow-through and closed-system methods. The atmospheres studied in the flow-through method were 5, 10, 15% v/v O2 (with the balance being N2), and ambient air. The respiration rates decreased after 6 days of storage except for the mushrooms at 5% O2, in which the respiration rate increased probably due to anaerobic fermentation. The respiration rates obtained from flow-through method were not a function of the oxygen concentration. However, the respiration rates obtained using the closed-system method were a linear function of the oxygen concentration. Since the respiration rate data obtained by closed-system were during the time when the mushroom adapts to the new environment the data cannot be used for designing MAP. The data obtained from the flow-through system should be used for the design of MAP.

Impacts
Understanding of the diffusion in food materials will assist in improved product design for better performance and increased shelf life. The results of our study can be utilized in developing coatings resistant to moisture migration. The approach for understanding diffusion through chocolate-based coatings outlined in this study can be extended to study diffusion of water as well as other molecules through heterogeneous food systems.

Publications

  • Ghosh, V. and Anantheswaran, R.C. 2003. Unsteady state heat transfer. In: Encyclopedia of Agricultural & Food Engineering (Ed. D.R. Heldman). Marcel Dekker. 1086 pp
  • Ghosh, V., Floros, J.D. and Anantheswaran, R.C. 2003. Refrigerants. In: Encyclopedia of Agricultural & Food Engineering (Ed. D. R. Heldman). Marcel Dekker. 827 pp
  • Anantheswaran, R.C. and Swanderski, J. 2003. Effect of electrical shielding and salt concentration on microwave heating in cylindrical containers. J. Microwave Power & Electromagnetic Energy 37(4):191-206
  • Ghosh, V., Ziegler, G.R. and Anantheswaran, R.C. 2003. Fat, moisture and ethanol migration through chocolates and confectionery coatings. CRC Reviews in Food Sci & Nutrition 42(6):583.
  • Chen, H., Anantheswaran, R.C. and Knabel, S.J. 2003. Effect of rapid cooling on the growth and penetration of Salmonella enteritidis into egg contents. J. Food Safety 22(4):255.
  • Pandrangi, S., Elwell, M.W., Anantheswaran, R.C. and LaBorde, L.F. 2003. Efficacy of sulfuric acid scarification and disinfectant treatments in eliminating Escherichia coli O157:H7 from alfalfa seeds prior to sprouting. J. Food Science 68:613.
  • Ghosh, V. 2003. Moisture migration through chocolate-flavored coatings. Ph.D. thesis, Pennsylvania State University, University Park, PA. 220pp.


Progress 01/01/02 to 12/31/02

Outputs
Moisture diffusion in food materials is of fundamental importance to many food processes. There is a huge spread in the moisture diffusion data in the literature, and very little information is available on the mechanism of diffusion. The spread in the diffusion coefficient is due to the fact that foods are heterogeneous multiphase materials and each food material has a different interaction with moisture. Researchers in chemical engineering have shown that diffusion of small molecules can be better understood when thermodynamics is coupled with the kinetic aspects. In this study, an attempt is made to use the approach suggested by Weisz (1967) to understand diffusion in a model food system containing fat and cocoa powder. The diffusion coefficient for moisture diffusing through fat was obtained by sorption experiments. Moisture sorption isotherms for sugar and cocoa powder was obtained by equilibrating them over saturated salt solutions. The predicted diffusion coefficient through a coating containing fat and varying amounts of cocoa powder was determined by incorporating the diffusivity data from the sorption experiments and the partition coefficient obtained from the moisture sorption isotherms. Experiments were conducted with coatings containing different amounts of cocoa powder to validate the model. From the preliminary results obtained so far there is a good agreement between the predicted values and the experimental data. Micro-perforated films are increasingly being used in modified atmosphere packaging (MAP) and modified humidity packaging (MHP) of fruits and vegetables with high respiration rates. In the design of MAP and MHP of fruits and vegetables, the knowledge of film permeabilities to oxygen and water vapor are essential. A patent has been granted for the experimental setup that was developed for measuring the oxygen transmission rate of micro-perforated films. Work is being continued to develop a technique to measure the water vapor transmission ratios of micro-perforated films. U.S. Patent issued #6422063, 23 July 2002.

Impacts
Understanding of the diffusion in food materials will assist in improved product design for better performance and increased shelf life. Understanding permeability of food packaging films will help to develop better packages for fresh and minimally processed food products.

Publications

  • Liang, L., Anantheswaran, R.C., Bradley, M.J. and Long, B.R. 2002. Characterization of Guided Microwave Spectrometry using water-ethanol mixtures. J. Microwave Power & Electromagnetic Energy 37(1):63.
  • Chen, H, Anantheswaran, R. C. and Knabel, S. J. 2002. Effect of rapid cooling of shell eggs on microcrack development, penetration of Salmonella enteritidis, and eggshell strength. J. Food Processing & Preservation 26(1):57.
  • Anantheswaran, R. C. and Roy, S. 2002. Factors affecting shelf life of fresh mushrooms. In: Manual for the cultivation of Pleurotus (Ed.J.E. Sanchez-Vazquez & D. Royse). Pg. 239-258. ECOSUR, Mexico.


Progress 01/01/01 to 12/31/01

Outputs
The GMS spectra and dielectric properties of water-ethanol mixtures with ethanol contents (v/v) of 0, 25 and 50% were measured at 10'C, 23'C and 40'C. The effects of coaxial cables and antenna were examined and the detection limits of the GMS analyzer were determined. The dielectric properties of the material being measured affected the GMS spectrum by shifting the cutoff region and changing the spectral amplitude over the entire operating frequency span. Temperature affected the spectrum by changing the dielectric properties of the material. Coaxial cables did not have a significant effect on the spectrum and the characteristic dip in the passband region was due to antenna resonance. The antenna affected the number of the resonances present in the spectrum, the frequency location and the amplitude of the resonances Micro-perforated films are increasingly being used in modified atmosphere packaging (MAP) and modified humidity packaging (MHP) of fruits and vegetables with high respiration rates. Work is being continued to develop a technique to measure the water vapor transmission ratios of micro-perforated films. The effect of rapid cooling on microcracks development in eggshell, eggshell strength, and the penetration and growth of S. enteritidis in egg contents were studied. It was found that rapid cooling produced microcracks in eggshells. However, the microcracks did not increase the penetration of S. enteritidis into egg contents when eggs were immersed in S. enteritidis culture for 24 or 48 h. When egg contents alone were sampled for S. enteritidis, extending the immersion time from 24 to 48 h significantly increased the penetration of S. enteritidis into egg contents from 5.0% to 25.0%. When egg contents together with eggshells were sampled, S. enteritidis was detected in 100% of the egg samples at the above two time intervals, indicating that, in most eggs, S. enteritidis accumulated in the shell pores and/or shell membranes, and did not penetrate through shell membranes. There were no significant differences in the eggshell strength between control and rapid cooling treatments, indicating that rapid cooling using these methods did not affect eggshell strength. Rapid cooling and subsequent storage of eggs at 6.6 - 7.2'C inhibited the growth of S. enteritidis in egg yolk and albumen. However, traditional cooling, and/or temperature abuse during storage promoted the growth of S. enteritidis in yolk and albumen. There was no significant difference in penetration of S. enteritidis into egg contents between the traditional cooling treatment and rapid cooling treatments (p>0.05), indicating that rapid cooling did not weaken the ability of the egg defense system in preventing bacterial penetration.

Impacts
GMS studies has the potential to develop a non-invasive sensor technique to measure quality attributes of food products during processing. The work on understanding permeability of food packaging films will help to develop better packages for fresh and minimally processed food products. Methods for rapid cooling of eggs is needed to ensure the safety of fresh eggs by preventing the growth of S/ enteritidis.

Publications

  • Chen, H., Anantheswaran, R. C. and Knabel, S. J. 2001. Optimization of iron supplementation for enhanced detection of Salmonella enteritidis in eggs. J. Food Protection 64(9):1279.
  • Chikthimmah, N., Anantheswaran, R.C., Roberts, R., Mills, E.W. and Knabel, S.J. 2001. Influence of sodium chloride on growth of lactic acid bacteria and subsequent destruction on E. coli 0157:H7 during Lebanon bologna processing. J. Food Protection 64(8):1145.
  • Ghosh, V. and Anantheswaran, R. C. 2001. Oxygen transmission rate through microperforated films: Measurement and model comparison. J. Food Process Engineering 24:113.
  • Anantheswaran, R. C. and Ramaswamy. H. S. 2001. Bacterial destruction and enzyme inactivation during microwave heating. In: Handbook of Microwave Technology for Food Application (Ed. Datta & Anantheswaran). Marcell Dekker, Inc. pg 191-213.
  • Shukla, T. P. and Anantheswaran, R. C. 2001. Ingredient interactions and product development for microwave heating. In: Handbook of Microwave Technology for Food Application (Ed. Datta & Anantheswaran). Marcell Dekker, Inc. pg. 355-395.
  • Books: Datta, A. K. and Anantheswaran, R. C. 2001. Handbook of Microwave Technology for Food Applications. Marcell Dekker, Inc. 511 pp.
  • Chen, H., Anantheswaran, R. C. and Knabel, S. J. 2001. Effect of rapid cooling and temperature of storage on the growth of Salmonella enteritidis in eggs. Paper presented at the 2001 Annual Meeting of IFT, New Orleans, LA June 23-27. IFT Annual Meeting Book of Abstracts, Abstract #59F-3, pg. 145.
  • Pandrangi, S., Martin, J. D., Anantheswaran, R. C. and LaBorde, L. F. 2001. Efficacy of sulfuric acid scarification in eliminating Escherichia coli o157:H7 from alfalafa seeds prior to sprouting. Paper presented at the 2001 Annual Meeting of IFT, New Orleans, LA June 23-27. IFT Annual Meeting Book of Abstracts, Abstract #59E-18, pg. 143.
  • Anantheswaran, R. C. 2000. Irradiation: Is it consumer friendly? Case Studies in Science Collection. A web based collection of cases peer reviewed and published by the University of Buffalo, Buffalo, NY. http://ublib.buffalo.edu/libraries/projects/cases