title: Comparative study on pressure and temperature stability of 5-methyltetrahydrofolic acid in model systems and in food products.
abstract: A comparative study on the pressure and temperature stability of 5-methyltetrahydrofolic acid (5-CH(3)-H(4)folate) was performed in model/buffer systems and food products (i.e., orange juice, kiwi puree, carrot juice, and asparagus). Effects of pH and ascorbic acid (0.5 mg/g) on 5-CH(3)-H(4)folate stability in buffer systems were studied on a kinetic basis at different temperatures (from 65 to 160 degrees C) and different pressure/temperature combinations (from 100 to 700 MPa/from 20 to 65 degrees C). These studies showed that (i) the degradation of 5-CH(3)-H(4)folate in all model systems could be described by first-order reaction kinetics, (ii) the thermostability of 5-CH(3)-H(4)folate was enhanced by increasing pH up to 7, (iii) 5-CH(3)-H(4)folate was relatively pressure stable at temperatures lower than 40 degrees C, and (iv) ascorbic acid enhanced both the thermo- and barostabilities of 5-CH(3)-H(4)folate. In food products, temperature and pressure stabilities of 5-CH(3)-H(4)folate were studied at different temperatures (70-120 degrees C) and different pressure/temperature combinations (from 50 to 200 MPa/25 degrees C and 500 MPa/60 degrees C). 5-CH(3)-H(4)folate in orange juice and kiwi puree was relatively temperature (up to 120 degrees C) and pressure (up to 500 MPa/60 degrees C) stable in contrast to carrot juice and asparagus. Addition of ascorbic acid (0.5 mg/g) in carrot juice resulted in a remarkable protective effect on pressure (500 MPa/60 degrees C/40 min) and temperature degradation (120 degrees C/40 min) of 5-CH(3)-H(4)folate.
authors.affiliation: Faculty of Agricultural and Applied Biological Sciences, Department of Food and Microbial Technology, Laboratory of Food Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium.
authors.lastname: Indrawati
authors.forename: C
authors.initials: C
authors.lastname: Arroqui
authors.forename: I
authors.initials: I
authors.lastname: Messagie
authors.forename: M T
authors.initials: MT
authors.lastname: Nguyen
authors.forename: A
authors.initials: A
authors.lastname: Van Loey
authors.forename: M
authors.initials: M
authors.lastname: Hendrickx
mesh_terms: D001205:Ascorbic Acid; D001628:Beverages; D004355:Drug Stability; D005502:Food; D005638:Fruit; D006863:Hydrogen-Ion Concentration; D011312:Pressure; D013696:Temperature; D013763:Tetrahydrofolates / Q000737:chemistry*; D014675:Vegetables
chemical_list: D013763:Tetrahydrofolates; D001205:Ascorbic Acid; C005984:5-methyltetrahydrofolate