Aromatase inhibitors in food – processing matters

Introduction: Various flavonoids possess a partial structure similar to the physiological substrates testosterone and androstenedion and are therefore enhancers or inhibitors of aromatase, as well as modulators of 17ß-estradiol receptors ERα and ERβ. The objective of this work is to quantify remainders of aromatase-modulating phytochemicals after processing and to identify suitable gentle preparation procedures.

Methods: A selection of flavonoid-rich food was prepared using BFH standard recipes. Expected analytes were extracted gently from raw and processed food using methanol/water 50: 50, containing ascorbic acid 250 mg/L and EDTA 25 mg/L. Flavonoid were assayed in triplicate using UPLC/high resolution mass spectrometry, carotenoids with the official Swiss Food Code HPLC.

Results and Discussion: The following relative contents (%) remain after processing compared to fresh foodstuff:

Remainder after processing (rel. contents in %)	Italian sugo	steamed tomatos	blueberry jam	steamed Mungo sprouts	gently roasted Mungo sprouts	green tea prepared at 80 °C
Lutein	95	41
ß-carotene	79	30
Lycopene	54	18
Quercitrin			90			112
Cyanidin			3
Genistein				21	24
Daidzein				32	34
Daidzin				61	91
Rutin				66	103	89
Vitexin-2-O-rhamnoside				85	132
Epigallocatechin						94
Epigallocatechingallat						54
Epicatechingallat						50
Gallocatechin						59
Gallic acid						135
Caffeine						54

Values of > 100% indicate better extractability after decompartmentation than from raw material. Tomato ingredients seem to be steam-volatile. Anthocyanidines in blueberries are substantially degraded by long heating processes. Gentle roasting is suitable for conserving Mungo sprouts components. Relevant amounts of substrates were not detectable in raw nor in processed mushrooms. N-containing substances from mushrooms disappear after processing due to thermal instability.

Conclusions: Loss of precious phytochemicals during processing is related to excess steam and heat. Food cultivated in the dark such as sprouts and mushrooms cannot biosynthesize relevant amounts of secondary phytochemicals due to the lack of light and temperature. Opposite claims of preventing aromatase- and estradiol-receptor-associated diseases seem to be illusive.

Disclosure of conflict of interests: nothing to declare