Sulfur-Containing Compounds: Natural Potential Catalyst for the Isomerization of Phytofluene, Phytoene and Lycopene in Tomato Pulp.

Lulu Ma,Qun Wang,Cheng Yang,Lianfu Zhang,Jian Zhang,Xin Jiang

doi:10.3390/foods10071444

Abstract

The effects of some sulfur-containing compounds on the isomerization and degradation of lycopene, phytofluene, and phytoene under different thermal treatment conditions were studied in detail. Isothiocyanates such as allyl isothiocyanate (AITC) and polysulfides like dimethyl trisulfide (DMTS) had the effect on the configuration of PTF (phytofluene), PT (phytoene), and lycopene. The proportion of their naturally occurring Z-isomers (Z1,2-PTF and 15-Z-PT) decreased and transformed into other isomers including all-trans configuration, while Z-lycopene increased significantly after thermal treatment, especially for 5-Z-lycopene. The results showed that increase in heating temperature, time, and the concentration of DMTS and AITC could promote the isomerization reaction effectively to some extent. In addition, 15-Z-PT and the newly formed Z4-PTF were the predominant isomers in tomato at the equilibrium. Unlike the lycopene, which degraded significantly during heat treatment, the isomers of PTF and PT were stable enough to resist decomposition. Moreover, the isomerization of three carotenoids was enhanced, and the bioaccessibility of lycopene increased significantly with the addition of shii-take mushroom containing sulfur compounds, while there was no positive effect observed in that of PTF and PT.

Highlights

Huabei pharmaceutical factory; phytofluene and phytoene(a mixture of E/Z isomers) were purchased from Carotenature, Switzerland; methanol, acetonitrile, and methyltert-butyl ether (MTBE) for chromatography were HPLC grade purchased from Oceanpak, Sweden; ethyl acetate, hexane, methanol, and acetone for extraction were analytical grade purchased from Sinopharm, China
Different types of isothiocyanates (MITC, butyl isothiocyanate (BITC), allyl isothiocyanate (AITC)) and polysulfides (DADS, diallyl trisulfide (DATS), dimethyl trisulfide (DMTS)) were first dissolved in olive oil at a concentration of 20 mg/g, and 5% olive oil with or without sulfur-containing compounds was blended into tomato pulp as a mediator of the E/Z-isomerization
All-E-lycopene accounted for 80.1–86.5% and the proportion of 5-Z-lycopene was about 6%, the others isomers were represented in cis-configuration, which was in accordance with the report of Colle et al [34]

Summary

Introduction

Numerous epidemiological studies showed that tomato consumption can reduce the risk of many cancers, including breast and prostate cancer [3,4], as well as chronic diseases such as cardiovascular disease [5] and diabetes [3]

Objectives

Methods

Results

Conclusion