Y.-H. P. Hsieh

Jellyfish as food.

Jellyfish have been exploited commercially by Chinese as an important food for more than a thousand years. Semi-dried jellyfish represent a multi-million dollar seafood business in Asia. Traditional processing methods involve a multi-phase processing procedure using a mixture of salt (NaCl) and alum (AlK[SO4]2ċ12 H2O) to reduce the water content, decrease the pH, and firm the texture. Processed jellyfish have a special crunchy and crispy texture. They are then desalted in water before preparing for consumption. Interest in utilizing Stomolophus meleagris L. Agassiz, cannonball jellyfish, from the U. S. as food has increased recently because of high consumer demand in Asia. Desalted ready-to-use (RTU) cannonball jellyfish consists of approximately 95% water and 4–5% protein, which provides a very low caloric value. Cannonball jellyfish collagen has shown a suppressing effect on antigen-induced arthritis in laboratory rats. With the great abundance of cannonball jellyfish in the U. S. coastal waters, turning this jellyfish into value-added products could have tremendous environmental and economic benefits.

Tea preparation and its influence on methylxanthine concentration

The amount of tea or coffee estimated from the number of cups consumed is frequently used as an indication of caffeine consumption in epidemiologic studies. However, this alone may be an inadequate indication of intake since drinking practices of tea varies. In this study, methylxanthine (caffeine, theobromine, and theophylline) contents in three brews of four types of tea (black, oolong, green, and herbal) in both bags and loose leaf forms were investigated to determine the actual amount of methylxanthines present in tea as a function of different brewing methods. On a dry leaf weight basis, total caffeine after three brews was highest in black (32.8 mg/g) and green (36.6 mg/g) tea leaves and lowest in Formosa oolong tea 2 (23.8 mg/g). Total theobromine was highest in black teas (1.64 and 1.69 mg/g) and least in oolong teas (0.65 and 0.71 mg/g). Caffeine and theobromine were not detected in either herbal tea samples, and theophylline was not detected in any tea tested. The overall average caffeine released in the first through third brews were 69%, 23%, and 8%, respectively. Three cups of tea brewed using three tea bags (Western culture) have approximately twice the amount of methylxanthines as the same volume prepared by three successive brews of loose tea leaves (Asian culture). These differences should be accounted for by the epidemiologic studies evaluating the effect of methylxanthines on health.

Potential of utilizing jellyfish as food in Western countries

Abstract Jellyfish are dodged by swimmers and a plague to fishermen. Although shunned in Western countries, jellyfish has a great potential value as a food item in the Orient. For over a thousand years, Chinese people have been eating jellyfish and have also regarded it as a treatment for high blood pressure, bronchitis and a multitude of other diseases. Processed jellyfish has a special crunchy and crispy texture that makes it unique. Extremely low in fat, cholesterol, salt and calories, jellyfish makes an ideal natural diet food. With proper development in the Western marketplace, jellyfish has the potential to be accepted as a food and to result in a new seafood industry.

Monoclonal antibodies against troponin I for the detection of rendered muscle tissues in animal feedstuffs

Regulatory controls to prevent the spread of BSE have prohibited the use of certain animal proteins in feed in several countries. Accurate analytical methods for detecting prohibited material in feedstuffs are needed to ensure compliance with the new regulations. Six IgG class monoclonal antibodies (MAbs) against troponin I (TnI), a thermostable marker protein, have been developed for the detection and differentiation of rendered muscle tissue in animal feed. MAbs 1F9, 2G3 and 7F7 reacted to TnI of all species, including mammalian, poultry and fish, while MAbs 7A12 and 8A12 recognized only mammalian TnI (porcine, bovine, ovine, equine, and deer). MAb 2A8 was able to differentiate TnI of ruminant origin (bovine, ovine and deer) from other species. Three indirect enzyme-linked immunosorbent assays (ELISAs) employing these MAbs were developed for the determination of animal muscle, mammalian muscle or ruminant muscle in animal feeds.

Production and partial characterization of monoclonal antibodies specific to cooked poultry meat

Monoclonal antibodies (MAbs) specific to cooked poultry muscle proteins have been developed for the detection of poultry adulterants in cooked mammalian meat. Saline (0.85% NaCl) extract of heat-treated (100 °C, 15min) chicken muscle proteins was used to immunize mice for MAb development. The specificity of MAbs was tested against chicken antigen and protein extracts from seven other meat species (pork, beef, lamb, deer, horse, turkey and duck) by indirect enzyme-linked immunosorbent immunoassay (ELISA). The immunogenic components in the poultry protein extracts were determined by SDS-PAGE followed by immunoblotting. A total of six hybridoma cell lines that secrete IgG class MAbs have been developed: MAbs 3E12 and 1A5 were able to distinguish between cooked poultry and mammalian meats, MAbs 9C6 and 6F7 reacted strongly with cooked chicken only, and MAbs, 5D2 and 6G8, reacted with both cooked turkey and chicken but not other species. All six MAbs demonstrated a proportional increased ELISA response to respective adulterated poultry samples in pork over a 0-100% range of aduleration.

Production and characterization of monoclonal antibodies specific to pangasius catfish, basa, and tra

Four IgG (subclass IgG1) class monoclonal antibodies (MAbs) strongly reactive to Asian farm-raised Pangasius catfish, tra (Pangasius hypophthalmus) and basa (Pangasius bocourti), have been developed. These MAbs were raised by immunizing an animal with thermal-stable crude sarcoplasmic protein extract of cooked tra. The MAbs were selected by screening hybridoma clones against more than 70 common fish and meat protein extracts. Two MAbs, T7E10 and T1G11, were found to be specific to the Asian Pangasius catfish, tra, and basa, with no cross-reactions with any of the common fish and meat species or with the food additive proteins (bovine serum albumin, soy proteins, milk proteins, egg proteins, and gelatin) tested. MAb T7E10 recognized 2 antigenic proteins (molecular weight approximately 36 and 75 kDa) in raw and cooked tra and basa extracts, while T1G11 bound to several proteins (molecular weight between 13 and 18 kDa) in tra and basa extracts. Two other MAbs, F7B8 and F1G11, recognized a common protein (36 KDa) and cross-reacted with all the fish extracts tested and with several mammalian species. These MAbs can be employed individually or in combination in various formats of immunoassays for rapid identification of Pangasius catfish, either raw or cooked. They can also be used to study the biological, biochemical, and physiological aspects of thermal-stable antigenic proteins. This is the first study identifying these thermal-stable antigenic proteins present in Pangasius catfish as species-specific biomarkers.

Monoclonal Antibodies against Heat-Treated Muscle Proteins for Species Identification and End-Point Temperature Determination of Cooked Meats

Quality and safety of muscle foods have been a concern of consumers and regulatory authorities. Enzyme-linked immunosorbent assay (ELISA) has been recognized as a sensitive and suitable analytical method in muscle foods for quality control and enforcement of food safety and labeling regulations. Several monoclonal antibodies (Mabs) have been developed as probing agents in ELISA for quantitative identification of adulterated meat species in fully cooked products. The Mabs developed were raised against heat-treated muscle proteins. The extent of heat treatment of a particular meat species could also be determined by these Mabs by comparing the increased ELISA response with the increase end-point cooking temperature. Therefore, these Mabs could be used to determine the maximum internal cooking temperature of a precooked meat sample to ensure safety of products. A brief review of current techniques and the experimental approach, characterization, and applications of these Mabs are addressed in this chapter

Kinetics of tropomyosin denaturation as a predictive model for verifying thermal processing of beef products.

An enzyme-linked immunosorbent assay (ELISA) was developed to study thermal denaturation of tropomyosin (Tm) using the time-temperature requirements for cooked beef. The ELISA employed a monoclonal antibody (MAb 2C9) raised against bovine Tm for quantifying residual Tm in muscle extracts. The specificity of MAb 2C9 to bovine Tm was demonstrated by Western blot and the analytical validity of ELISA was confirmed by dot blot. Thermal denaturation of Tm, in the temperature range between 54.4 and 70.0 degrees C, showed first-order dependency. Kinetic parameters of Tm denaturation were derived from isothermal heating of beef muscle extract at 54.4, 57.2, 60.0, and 62.8 degrees C. Temperature dependency of the rate constant (k) was demonstrated by Arrhenius plot; the activation energy (E(a)) of Tm denaturation was determined to be 484 kJ x mol(-1). A mathematic model describing the impact of the heating time-temperature on Tm denaturation was developed. Predicted Tm from the integrated time-temperature model agreed closely with the measured Tm in dynamically heat-processed beef samples. Percent errors between the measured and the predicted values ranged from -5.1 to 5.3%. The kinetic model provides an accurate and reproducible prediction of the impact of actual heating time-temperature on residual Tm in cooked beef. The MAb-based ELISA and kinetic model developed in this study have the potential to be adapted by the meat industry as a quality control tool.