The impact of hydrothermal treatments on vitamin B6 degradation in chickpeas
Date
2024-05
Authors
Shaban, Heba Mustafa
Major Professor
Advisor
Delchier, Nicolas
Talbert, Joey
Stephanie, Clark
Watrelot, Aude
Hollis, James
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Abstract
Legumes, encompassing a diverse range of peas, beans, lentils, and peanuts within the Fabaceae family, are crucial components in global food systems. Pulses, which are the dried seeds of leguminous plants, are known for their high nutritional value. Vitamin B6, plays a significant role in various metabolic processes and overall health. Acting as a cofactor, vitamin B6 participates in about 160 metabolic reactions within the human body. However, the vitamin content of pulses may vary during processing. The raw chickpeas contain an average concentration of 0.630 mg/100g of vitamin B6, while canned chickpeas with added salt contain 0.046 mg/100g of vitamin B6 (Andac-Ozturk et al., 2022; Patil et al., 2020). Despite vitamin B6 importance, limited research has explored the mechanisms underlying the degradation of vitamin B6 during processing, particularly in pulses. Factors such as temperature, moisture content, pH level, and light intensity can affect the water-soluble vitamin content in pulses during processing.
This study aimed to better understand the mechanisms underlying vitamin B6 loss during chickpeas hydrothermal processing. The first objective was to develop a method for accurately quantifying the amount of vitamin B6 in chickpea samples, and the second objective was to investigate the relative role of diffusion and thermal degradation in the vitamin loss during hydrothermal treatment.
The method used for vitamin B6 quantification in chickpeas was adapted from the AOAC method (Mann et al., 2005) with some modifications. Briefly, enzymatic hydrolysis was used to extract B6 vitamers from the chickpea sample, followed by a reduction of pyridoxal (PL) into pyridoxine (PN), using sodium borohydride. The vitamin B6 was separated on a High Performance Liquid Chromatography and detected by a fluorimetric detector (HPLC-FLD). This modified method was validated based on the linearity of the standard curve, the coefficient variation percentage (CV) of PN standards, and an interlaboratory assay, The Limit of Detection (LOD) and the Limit of Quantification (LOQ). All results were within the acceptable limits defined in the literature. The method demonstrated good precision, with a coefficient of variation (CV) for the PN peak below 0.33%. The LOD and LOQ were calculated as 0.06 μg/mL and 0.19 μg/mL, respectively. The study revealed that the concentration of total vitamin B6 in chickpeas was 0.217 ± 0.01 mg/100g of fresh weight.
Understanding of the relative role of thermal degradation and leaching in the overall loss of the vitamin B6 in chickpeas was performed using a kinetic approach. Diffusion kinetics were carried out after a boiling treatment of 30 min, in an excess of water at four different temperatures (25 ºC, 45 ºC, 65 ºC, and 85 ºC) and for 240 min. Thermal degradation kinetics were performed in the same temperatures and time duration, except that chickpeas were placed in a hermetic bag for the kinetics. Samples were collected at 0, 5, 10, 15, 60, 120, 150, and 240 min, directly stabilized by freezing in liquid nitrogen, and stored at -80 ºC until analysis. Quantifying of the total vitamin B6 content was performed using the modified AOAC method. Data were modeled and the rate constant k was determined using a first-order law. At the same time, the diffusivity constant was determined using the second Fick’s law for the diffusion. Diffusivity constants varied from 4.76 ×10-14 m2/s at 25 °C to 2.07 ×10-14 m2/s at 85 ºC, with an impact of the temperature on both the constant D and the residual content. The kinetic constant k ranged from 9.35 ×10-6 at 25 ºC to 54.9 ×10-6 s-1 at 85 ºC, with a lower impact of the temperature. Vitamin B6 loss is mainly due to diffusion, especially during shorter treatment times, and seems more stable than expected regarding heat treatment.
Series Number
Journal Issue
Is Version Of
Versions
Series
Academic or Administrative Unit
Type
thesis