Effect of pulse electric fields and fermentation on phytate, RFOs and protein digestibility of yellow pea

Abstract

Phytates and RFOs are known anti-nutrients found in pulses, that can impair mineral absorption and cause digestive discomfort, respectively. Pulsed electric field (PEF) have emerged as a promising technology, for cell membrane permeabilization, potentially enhancing the accessibility of these compounds to enzymatic degradation. Fermentation, on the other hand, is a traditional method known to reduce anti-nutrient content in various food matrices. In this experiment it was of interest to use fermentation and PEF, separately and combined on Swedish yellow pea to understand if this could lead to an enhanced nutritional profile.

Through a series of experiments, whole yellow peas and yellow pea flour were subjected to various PEF treatment parameters, including 2 kV/cm and 4 kV/cm at 50 kJ/kg for pea flour, and 5 kV/cm and 8 kV/cm at 100 kJ/kg for whole peas. Additionally, fermentation was conducted with Lactiplantibacillus plantarum 299v, and the pulses were fermented for up to 9 hours at 37℃. Alongside the separate treatments, a combination of PEF followed by fermentation was applied as well. The effectiveness of these treatments in reducing phytate and RFOs, as well as evaluating protein digestibility, was assessed.

A significant decrease in RFOs was observed for whole peas on all treatments when compared to untreated peas. There was no significant difference for pea flour, when comparing the control with both PEF-treatments alone. However, when comparing pea flour with the fermented flour and fermented combined with PEF-treatment, a significant reduction was observed.
The phytate content was significantly reduced when comparing whole pea with soaked pea and PEF 5 kV/cm-fermented pea. For the pea flour a significant difference was observed between untreated pea flour, PEF 4 kV/cm and PEF 2 kV/cm – fermented.

Protein content analysis revealed that the combined treatment of PEF and fermentation (PEF 2 kV/cm-Fermented pea flour and PEF 5 kV/cm-Fermented whole pea) exhibited the highest protein content. With no significant increase in pea flour, whereas a significant increase was observed between control and whole pea - PEF 5 kV/cm-fermented. Furthermore, protein digestibility following in vitro digestion increased across all treated samples, except PEF 5 kV/cm for whole pea, having almost similar value as the control pea. With flour PEF 2 kV/cm and whole pea PEF 5kV/cm-fermented samples showing the highest significant values at 75.42% and 75.44%, respectively.

In conclusion, these findings suggest that PEF and fermentation are promising strategies for improving the nutritional quality of pulses. Especially, when the treatments were combined the greatest effect was observed. Whole pea subjected to PEF 5 kV/cm and fermentation had a significant decrease in both RFOs and phytate content. In addition, it had the highest protein content and protein digestibility value for whole pea. For pea flour subjected to PEF 2 kV/cm and fermentation, showed a significant decrease in RFOs and phytate. Further, it had the highest protein content (among the flour treatments) and second highest protein digestibility value.

Popular Abstract

The demand for plant-based food-products has increased significantly in recent years, highlighting the pivotal role of legumes and pulses in plant-based diets. Pulses are nutritious foods rich in protein, fibre, starch, vitamins and minerals, which can be consumed alone or as a food ingredient in different food applications. However, despite their health benefits there are some nutritional challenges associated with pulses, such as antinutrients which may affect the impact of their adaption among consumers. A common antinutrient in pulses is phytate, known to hinder the absorption of iron and zinc, potentially leading to reduced mineral availability. Additionally, phytate has shown to reduce protein digestibility. Other challenges with legumes are that many people commonly experience flatulence when consuming pulses, which can limit their intake. This discomfort is widely attributed to the presence of raffinose family oligosaccharide (RFOs). Different processing methods including soaking, fermentation and emerging technologies has been employed to enhance the nutritional profile of pulses.

In this study the effectiveness of pulse electric field (PEF) as an emerging technology and lactic acid fermentation on improving nutritional profile of Swedish yellow pea, both in its whole grain and flour form was investigated and compared. The assessment focused on how these techniques affect phytate, RFOs, protein content and protein digestibility.

Contrary to the expected hypothesis of reduced phytate levels, only a minor decrease was observed. However, a notable reduction in RFOs was observed. This reduction positively impacts on protein digestibility as it was increased.

• author: de Jounge, Rebecca and Samaei, Yasaman
• supervisor: Claudia Lazarte
• organization: Food Technology and Nutrition (M.Sc.)
• course: KLTM02 20241
• year: 2024
• type: H2 - Master's Degree (Two Years)
• subject: Agriculture and Food Sciences
• keywords: PEF, Fermentation, RFOs, Phytic acid, Yellow pea, Food engineering, nutrition and food chemistry
• language: English
• id: 9156135
• date added to LUP: 2024-06-11 08:31:38
• date last changed: 2024-06-11 08:31:38