Submitted to: High Pressure Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2013
Publication Date: 12/19/2013
Citation: Chung, S., Houska, M., Reed, S.S. 2013. Reducing peanut allergens by high pressure combined with polyphenol oxidase. High Pressure Research. 33(4):813-821. Interpretive Summary: High pressure (HP) is a non-thermal technology that is widely used to sterilize foods, fruits, and vegetables. Polyphenol oxidase (PPO) is an enzyme that is commonly found in apples, and is responsible for the browning reaction in cut apples. Because PPO is reported to reduce peanut allergens in a peanut extract, and HP known to increase enzyme activity, we postulated that HP combined with PPO would further enhance the reduction of peanut allergens. To support this postulation, two different HP energy levels (300 and 500 MPa) were tested and applied in conjunction with, and without PPO to peanut protein extracts at 37 oC for 3 and 10 min, respectively. Results showed that HP by itself had no effect on peanut allergens. PPO itself reduced peanut allergens as expected,however, PPO combined with HP at 300 MPa did not enhance the reduction. Only when HP was at 500 MPa and combined with PPO, a 2-fold reduction of peanut allergens was observed. There was no difference between the treatment times. It was concluded that HP at 500 MPa combined with PPO (3 min) enhanced or resulted in a 2-fold reduction of peanut allergens, as compared to PPO itself. If confirmed by clinical studies, the research could lead to the development of less allergenic peanut-based beverages and products.
Technical Abstract: Polyphenol oxidase (PPO) has been shown to reduce major peanut allergens (Ara h 1 and Ara h 2). Because high pressure (HP) can increase enzyme activity, we postulated that further reduction of peanut allergens can be achieved through HP combined with PPO. Peanut extracts were treated with each of the followings: (1) HP, (2) HP + PPO, (3) PPO, and (4) none. HP was conducted at 300 and 500 MPa, each for 3 and 10 min. All treatments contained caffeic acid as the media for cross-linking of the allergens through PPO. After treatment, SDS-PAGE was performed and allergenic capacity (IgE binding) was determined colorimetrically in inhibition ELISA and Western blots, using a pooled plasma from peanut-allergic patients. Data showed that HP alone had no effect on major peanut allergens, however, HP at 500 MPa combined with PPO (HP500/PPO) induced a higher (approximately 2-fold) reduction of major peanut allergens and IgE binding than PPO alone or HP300/PPO. There was no difference between treatment times. We concluded that HP500/PPO enhanced or displayed a 2-fold reduction of major peanut allergens and IgE binding, compared to PPO itself, and that a 3-min treatment time was sufficient for the HP500/PPO treatment.