Proteins from plant-based biomass: effects of post-harvest conditions on protein retention and quality : Part II Yellow pea

Samenvatting

Wageningen University & Research is looking for ways to increase the availability and diversity of proteins. Plant proteins are an attractive alternative to animal proteins. It is important to optimize the recovery methods of proteins from plant based biomass sources. This includes the need to study the effects of post-harvest conditions on the yield and quality of extracted proteins.There is also an increasing interest in pea as protein source. Therefore, the effects of post-harvest conditions were studied on protein yield and quality in dried yellow peas. The peas were stored under two different temperatures (12 and 40 °C) combined with three relative humidity (RH) levels (range 26 to 86% RH) during four different storage periods (1, 2, 4 and 6 weeks). This led to differences in moisture content after 6 weeks, ranging from 4.8% at high temperature in combination with low RH till 17.6% at low temperature in combination with high RH. Analyses were done on protein content, protein composition, glycation, hexanal and saponins.Glycation of pea proteins is relevant for the possible improvement of techno-functional properties,such as solubility and interfacial properties. Hexanal and saponins are relevant components in peas which may cause or indicate off-taste in extracted pea protein. The main results of this study are as follows:• Overall, there was no clear effect of storage condition (temperature, RH) and storage period on protein content, as shown by BCA assays.• Storage conditions and storage period did not affect protein quality in terms of protein composition, as shown by SDS page.• We found no evidence of an effect of storage on the off-flavour compound hexanal.• The relative levels of saponins were measured, but besides potentially small changes at40°C/85%RH, the storage conditions tested did not seem to have an influence on saponin content and composition.• We found differences in glycation between samples. However, the results were not consistent. Nevertheless, it is an interesting finding that glycation can be affected in some way.The described results and conclusions are valid for yellow peas (whole seeds) under the testedcircumstances.The research was performed independently by researchers from Wageningen Food & Biobased Research, funded by the Ministry of Agriculture, Nature and Food Safety by DFI- R&D budget, within the strategic WUR-KB theme of Healthy and Safe Food.