A KINETIC APPROACH TO SAPONIN EXTRACTION DURING WASHING OF QUINOA (CHENOPODIUM QUINOA WILLD.) SEEDS

Abstract

The aim of this work was to show that the leaching process of saponins from quinoa (Chenopodium quinoa Willd.) seeds during washing with water, as is generally practiced by people in South America, can be modeled using mathematical expressions related to Fick's second law. Experimental data were obtained through batch extraction with a ratio of quinoa to water of 1:10 under constant agitation for processing time between 15 and 120 min at 20, 30, 40, 50 and 60C. It was found that residual saponin concentration in the quinoa seeds decreased as washing temperature increased. Leaching rate followed the Arrhenius relationship, with calculated effective saponin diffusion coefficient between (5.05 Ϯ 0.15) ¥ 10 -10 and (32.50 Ϯ 1.65) ¥ 10 -10 m 2 /s as the temperature increased from 20 to 60C. Several mathematical models to describe the kinetic behavior of the leaching process were analyzed. The modified Henderson-Pabis model had the best fit quality as shown by statistical analysis. PRACTICAL APPLICATIONSDuring processing of quinoa for human consumption, a washing process is necessary to remove most of the bitter saponins found in the seeds, as this type of saponin is considered to be a serious antinutritional factor. For industrial scale-up of this processing step, leaching behavior of the saponin is of crucial importance to find the best design parameters and the most cost-effective process conditions. This helps reduce energy waste and optimize water flow rate in a continuous washing process. The present study used well-known models to explain saponins' leaching kinetics from the quinoa seeds with water at different temperatures. The best mathematical model with its justification was also determined, which is generally the most economical way to proceed.

SO2-catalysed steam pretreatment of quinoa stalks

“…The reason was that these compounds could not be extracted successfully – possibly due to the presence of polar ‘sapogenins’ or other ‘unknown’ compounds interfering the extraction. A recent study has shown that aqueous extraction is not particularly efficient for removing saponins from quinoa seeds and a removal of only 32% was reported . In the present work, the amount of saponins were, however, low in all hydrolysates (data not shown).…”

Enhancement of the rancidity stability in a marine‐oil model by addition of a saponin‐free quinoa (Chenopodium quinoa Willd.) ethanol extract

“…Determination of total saponins (TS) content was carried out based on a modified reversed‐phase HPLC procedure described by Quispe‐Fuentes et al . For it, an HPLC device (Agilent 1200 Series HPLC system, Santa Clara, CA, USA) including a diode array detector (DAD) set at 210 nm and an automatic injector was employed.…”

Kinetic Study of Saponin Extraction from Sapindus rarak DC by Ultrasound-Assisted Extraction Methods

“…The data from kinetic studies are needed to design the production equipment such as reactor or extractor. Moreover, the kinetic model also improves the procedure precision, minimizing processing errors and increasing the final quality of the product [11][12].…”

“…However, there are few studies of extraction kinetics for saponin from Sapindus rarak DC. To our best knowledge, few studies have explained the saponin extraction kinetics, such as kinetic studies of saponin leaching from quinoa seed [12,16] and kinetic studies of saponin extraction from Saponaria vaccaria L. seeds [17]. The previous kinetic studies were focused on the leaching mechanism to obtain saponin, where the raw materials were only soaked for a specific time in a solvent.…”