# Improved Food-Processing Techniques to Reduce Isoflavones in Soy-Based Foodstuffs
## 1 Introduction
The no observable adverse effect level (NOAEL) could not be obtained from these studies, so a lowest observable adverse effect level (LOAEL) was alternatively proposed for both reproduction and carcinotoxic effects, which was 35 mg/kg bw/day in rats. Such a dose may help to determine a reference dose (RefD), i.e., a limit of exposure for humans. Additionally, as discussed by [PERSON] et al. [26], even if endocrine disruptors can be more deleterious at low doses, due probably to the activation of different pathways, as mentioned above, there is no evidence of any adverse effects of low IF doses in vivo and in humans. Rather, it is doses over 20-40 mg/d (aglycone-glycosic forms) that can exert physiological activities, either beneficial or deleterious, depending on the status of the consumer. In this context, a previous work [27] has already demonstrated at the laboratory level the feasibility of a strong reduction in the IF content of soybeans by a specific water treatment. An important issue ensued, and may be phrased by the following question: how can IFs' removal from soy matter be carried out on an industrial scale without degrading its nutritional quality and generating a heavy additional hurdle either? The purpose of the present investigation is (1) to provide a positive and convincing answer to this question by means of a pilot-scale study that could then be scaled up, (2) to mitigate the environmental impact and supplementary costs through water and energy savings, and (3) to recover IFs from treatment water to feed the phytochemical industry. Indeed, as IFs are active compounds, they could and should be used for health applications in rigorously controlled supplementation. Therefore, collecting them in soy-based food factories would also reduce unwanted environmental exposure. To do this, the approach utilised is as follows. (1) To determine the optimum experimental configuration of design factors those deemed relevant for IFs' removal [27] at the laboratory were first optimized by monitoring the content variations of the main soy IFs, GEN and daidzein (DAI) [33]. The individual impacts of these factors were evidenced by IF concentration measurements, taking advantage of the enzyme-linked immuno-sorbent assay (ELISA)'s high sensitivity and specificity. (2) To achieve improved treatment at pilot scale, the transposed data of the optimized laboratory factors were then readjusted. This was accomplished while exploring the impacts of unexpected (drenching) and relevant additional (granulometry, determined by laser diffraction and sieve analysis) factors. The whole process also implemented the supplementary constraint of the final step of drying the treated soybeans. (3) On another side, as the ELISA requires a rather long implementation, a faster assay method, i.e., Folin-Ciocalteu, was tested, since it appeared better suited to routine usage in an industrial environment. (4) The nutritional quality control of soy matter was performed by Phytocontrol(r) (Nimes, France) according to [PERSON]'s methods for proteins and gravimetry for lipids. (5) To study the feasibility and quality of water recycling as well as IFS recovery, centrifugation, filtration and resin adsorption were tested on treatment waters. Appropriate statistical analyses were performed, i.e., signal to noise ratios for laboratory study and a Mann-Whitney test for pilot-scale data. The results presented here are discussed under the realm of the potential exposure limit RefD, as defined above. The pilot-scale investigation resulted in the highlighting of a successful improved treatment that significantly reduced IF concentrations in soy.