title: Effect of enzyme activity and frozen storage on jalapeño pepper volatiles by selected ion flow tube-mass spectrometry.
abstract: Samples of unblanched (fresh), stannous chloride-treated, or blanched jalapeño peppers were measured for real-time generation of lipoxygenase-derived volatiles during 10 min after tissue disruption. Volatiles were also measured before and after 1.5, 2.5, 3, 6, and 9 mo of frozen storage at -15 °C. The concentration of all lipoxygenase-derived compounds was significantly higher in unblanched jalapeño peppers compared to enzyme inhibited peppers. The maximum concentration of (Z)-3-hexenal, (E)-2-hexenal, and hexanal was detected at about 1.2, 1.5, and 1.5 min after tissue disruption, respectively. A decrease in (Z)-3-hexenal and an increase in dimethyl sulfide and methylbutanal occurred in blanched compared to stannous chloride-treated peppers due to heat. Frozen storage resulted in no major changes in the lipoxygenase-derived volatiles of whole and pureed blanched peppers after 9 mo. However, in whole unblanched peppers a gradual decrease of (Z)-3-hexenal, (E)-2-hexenal, hexanal, hexenol, and hexanol was observed over time; whereas in pureed unblanched peppers these compounds increased, reached maximum concentration, and then decreased. Similarly, the minor volatiles 2-pentenal, 1-penten-3-one, (E)-2-heptenal, (E)-2-octenal, and (E)-2-nonenal showed an initial increase followed by a decline in both whole and pureed unblanched peppers. Tissue disruption increased generation and degradation rates during frozen storage. The compounds (E,Z)-2,6-nonadienal, n-propyl aldehyde, 2-isobutyl-3-methoxypyrazine, and a mixture of terpenes decreased in unblanched and blanched frozen samples, while nonanal and methylbutanal increased only in unblanched samples.
authors.affiliation: Dept. of Food Science and Technology, The Ohio State Univ., 2015 Fyffe Rd, Columbus, Ohio 43210, USA.
authors.forename: Carolina
authors.initials: C
authors.lastname: Azcarate
authors.forename: Sheryl A
authors.initials: SA
authors.lastname: Barringer
mesh_terms: D000447:Aldehydes / Q000032:analysis; D002212:Capsicum / Q000737:chemistry*; D005511:Food Handling / Q000379:methods; D005615:Freezing; D000441:Hexanols / Q000032:analysis; D008084:Lipoxygenase / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods*; D029222:Piper nigrum / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000447:Aldehydes; D000441:Hexanols; D055549:Volatile Organic Compounds; C008664:nonanal; C547093:2-methylbutanal; C051750:2-hexenal; C010463:n-hexanal; D008084:Lipoxygenase