Assessing the impact of nitrogen supplementation in oats across multiple growth locations and years with targeted phenotyping and high-resolution metabolite profiling approaches

J William Allwood,Pilar Martinez-Martin,Yun Xu,Alexander Cowan,Simon Pont,Irene Griffiths,Julie Sungurtas,Sarah Clarke,Royston Goodacre,Athole Marshall,Derek Stewart,Catherine Howarth

doi:10.1016/j.foodchem.2021.129585

J William Allwood, Pilar Martinez-Martin + Show 10 more

Open Access

https://doi.org/10.1016/j.foodchem.2021.129585

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Journal: Food chemistry	Publication Date: Mar 16, 2021
Citations: 10	License type: cc-by

Affiliation: Aberystwyth University, University of Liverpool

Abstract

Oats (Avena sativa L.) are a healthy food, being high in dietary fibre (e.g. β-glucans), antioxidants, minerals, and vitamins. Understanding the effect of variety and crop management on nutritional quality is important. The response of four oat varieties to increased nitrogen levels was investigated across multiple locations and years with respect to yield, grain quality and metabolites (assessed via GC- and LC- MS). A novel high-resolution UHPLC-PDA-MS/MS method was developed, providing improved metabolite enrichment, resolution, and identification. The combined phenotyping approach revealed that, amino acid levels were increased by nitrogen supplementation, as were total protein and nitrogen containing lipid levels, whereas health-beneficial avenanthramides were decreased. Although nitrogen addition significantly increased grain yield and β-glucan content, supporting increasing the total nitrogen levels recommended within agricultural guidelines, oat varietal choice as well as negative impacts upon health beneficial secondary metabolites and the environmental burdens associated with nitrogen fertilisation, require further consideration.

Highlights

Oats, Avena sativa L., are a cereal crop cultivated largely across temperate regions of the world providing a source of food for human consumption and animal-feeds, as well as providing a key source of emollients to the cosmetics industry (Marshall et al, 2013)
Grain yields did not continue to increase significantly beyond the addition of 200 kg N/ha, optimal levels could only be calculated for ADAS 2015 because for the other two trials the yields were continuing to increase above the highest level of nitrogen applied
Thousand grain weight (TGW) was significantly affected by nitrogen (Table 1) it was not correlated with grain yield

Summary

Introduction

Avena sativa L., are a cereal crop cultivated largely across temperate regions of the world providing a source of food for human consumption and animal-feeds, as well as providing a key source of emollients to the cosmetics industry (Marshall et al, 2013). Oats are commonly consumed as whole grains and have gained increased attention in recent decades due to their nutritional balance and large number of health benefits (Martínez-Villaluenga & Penas, 2017). They are renowned as a rich source of dietary fibre, in particular the soluble fibre β-glucan, as well as being high in antioxidants, minerals and vi tamins. Studies have shown that oat rich diets can directly be correlated with reduced blood pressure, bloodsugar and insulin levels, and increased satiety reducing the prev alence of obesity, risk of cardiovascular disease and Type II diabetes (as reviewed by Martínez-Villaluenga & Penas, 2017). The major storage proteins of oats, avenins, are believed to be less immunogenic to suf ferers of coeliac disease, making oats suitable for a gluten-free diet (Welch, 2011), the processing environment must be clean of other cereals

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