Field border flowering strips as a source of valuable compounds

Intensification of agricultural practices has caused irreversible damage to environment during the last few years. Several consumers are now deviating towards healthier diets produced from eco-friendly and sustainable agricultural systems. In this regard, the possibilities of utilizing edible biomass originating from sustainable agricultural practices have gained recent attention. The underutilized edible plants, especially their seeds could be one of the interesting alternates, as some of these seeds are not only nutritious, but could also be produced using sustainable practices. Similarly, edible insects represent another category of biomass which are rich in nutrients and could be produced sustainably. The seeds from underutilized edible plants and the edible insects could be simultaneously harvested using a sustainable agricultural system involving field border flowering strips. Field border flowering strip is a part of agricultural landscape that is reserved for herbaceous vegetation. These strips are popularly grown throughout the world to enhance biodiversity. The main objective of this thesis is to utilize seeds from some of the plants grown as field border flowering strips and insects that find refuge in these plants for the provision of food and health promoting substances.
From the literature reviewed in chapter two, it was observed that: (1). Most plants that are grown in field border flowering strips are edible, and their aerial parts have been extensively analyzed for chemical composition. However, there is a scarcity of literature evaluating chemical composition/food utilization of the seeds from plants that are grown as field border flowering strips. So, the primary objective of this thesis is to investigate the nutritional and health promoting potential of the seeds from some plants that are grown in these strips. (2). A number of grasshopper species find refuge in field border flowering strips. Several grasshopper species are considered edible throughout the world and they are interesting source of nutrients. So the secondary objective of this thesis is to screen some edible grasshopper species that are present in field border flowering strips, analyze their nutritional value, and investigate possibilities to establish their commercial rearing for ensuring year-long availability of edible biomass.
The research strategy adopted to achieve the objectives of this thesis is mentioned in chapter three. This chapter includes details about the selection of raw materials (both plant seeds and insects), and subsequent analysis. Chapter four contains the detail about the materials and methods used for analysis during this study.
Chapter five includes details about the investigations on edible insects. Chorthippus parallelus Zetterstedt species grasshoppers were shortlisted for detailed investigation due to their high densities in field border flowering strips. This insect species was analyzed for proximate composition, amino acid profile, fatty acid profile and mineral profile. Moreover the toxicity of these insects was also evaluated using two different models. Results indicated that these insects could be consumed as an alternate source of proteins (69%) and omega-3 fatty acid rich lipids (10%). Rearing trials done during this study indicates that commercial rearing could be developed to produce sufficient and safe biomass for human consumption.
The selection of seeds from three plant species (Achillea millefolium L., Anthriscus sylvestris (L). Hoffm. and Prunella vulgaris L.), for detailed analysis on the basis of lipid content and fatty acid profile has been mentioned in chapter six.
Chapter seven, eight and nine include the details about the composition and anti-oxidant activity of A. millefolium, A. sylvestris and P. vulgaris seeds, respectively. Proximate composition, lipid profile, amino acid profile, mineral profile, lignocellulosic profile, phenolic profile and phytate content of the three plant seeds were investigated during this study. Two new phenolic acids were discovered originating from P. vulgaris seeds. These compounds were named amolsamic acid A and amolsamic acid B. Discovery of these compounds was the true highlight of this thesis. All the three plant seeds were found to contain substantial level of total phenolics (0.8-2.6%) and interesting phenolic profiles (dominated by chlorogenic acid, rosmarinic acids and related compounds). Keeping this in mind, the detailed anti-oxidant activity (including anti-radical scavenging, horseradish peroxidase response modulation, cellular anti-oxidant, myeloperoxidase response modulation and anti-lipid peroxidation activity) of their respective seed extracts was also analyzed. Results obtained during this study indicate that A. millefolium, A. sylvestris and P. vulgaris seeds not only contain interesting level of nutrients, but their extracts also exhibit significant anti-radical scavenging, horseradish peroxidase response modulation, cellular anti-oxidant (IC50 values order: P. vulgaris>A. sylvestris>A. millefolium) and myeloperoxidase response modulation activity (IC50 values order: A. sylvestris>A. millefolium>P. vulgaris for both direct and SIEFED assay).
The main conclusions (chapter ten) of this PhD dissertation are: (1). C. parallelus insects could be viewed as an alternative source of nutrients to diversify human diets. The preliminary rearing studies done during this study indicate that commercial rearing could be developed for generation of substantial (and safe) biomass to support human consumption. (2). A. millefolium, A. sylvestris and P. vulgaris seeds could be included in food formulations (or consumed as whole) as a source of proteins, lipids, minerals and phenolics. P. vulgaris seeds could also be used for the extraction of two new phenolic constituents (amolsamic acid A and amolsamic acid B). The first investigations involving A. millefolium, A. sylvestris and P. vulgaris seeds realized during this study, indicate that seed extract (or whole seeds) from all three plants could possibly be consumed for the prevention of neutrophil and myeloperoxidase mediated damage in human body.