High throughput method development and optimised production of leaf protein concentrates with potential to support the agri-industry

Abstract

Invasive plants offer an interesting and unconventional source of protein and the considerable investment made towards their eradication can potentially be salvaged through their revalorisation. To identify viable sources, effective and high-throughput screening methods are required, as well as efficient procedures to isolate these components. Rigorous assessment of low-cost, high-throughput screening assays for total sugar, phenolics and protein was performed, and ninhydrin, Lever and Fast Blue assays were found to be most suitable owing to high reliability scores and false positive errors less than 1%. These assays were used to characterise invasive Scottish plants such as Gorse (Ulex europeans), Broom (Cystisus scoparius) and Fireweed (Chamaenerion angustifolium). Protein extraction (alkali-, heat- and enzyme assisted) were tested on these plants, and further purification (acid and ethanol precipitation, as well as ultrafiltration) procedures were tested on Gorse, based on protein recovery values. Cellulase treatment and ethanol precipitation gave the highest protein recovery (64.0 ± 0.5%) and purity (96.8 ± 0.1%) with Gorse. The amino acid profile of the purified protein revealed high levels of essential amino acids (34.8 ± 0.0%). Comparison of results with preceding literature revealed a strong association between amino acid profiles and overall protein recovery with the extraction method employed. The final purity of the protein concentrates was closely associated to the protein content of the initial plant mass. Leaf protein extraction technology can effectively raise crop harvest indices, revalorise underutilised plants and waste streams.

Plant Nutrition for Human Health: A Pictorial Review on Plant Bioactive Compounds for Sustainable Agriculture

“…For selecting medicinal plants, there are different strategies that can be used, as reported by [26] in Figure 10. Concerning plant functional traits and their potential for human health, there are several general themes such as antimicrobial plants [65,66], plant secondary metabolites [67], nutraceuticals for human health [68], plant leaf protein concentrates [69], biofortified plants for human health [70], plant-based diets for human diseases [17,71], and herbal bioactive-based products for different applications such as cosmetics [72,73]. Plant-based diets have important benefits for human health, which prevent or decrease many human diseases such as cardiovascular, dermatological, endocrinological, gastrointestinal, ophthalmological, genitourinary, otolaryngological, musculoskeletal, neurological, and respiratory diseases [65].…”

Potential Applications of the Cytisus Shrub Species: Cytisus multiflorus, Cytisus scoparius, and Cytisus striatus

“…The chemicals used as herbicides cause problems such as losing local flora and contamination in underground water supplies [32]. In recent years, the circular economy concept has gained significant relevance.…”

“…By being rich in essential amino acids, these protein concentrates are necessary for the human diet. The work of Ajay et al [32] aimed to take a species considered invasive in Scotland, C. scoparius, and apply various methods of leaf protein extraction. Leaf samples of the species were treated with a phosphate buffer solution and subjected to multiple forms of protein estimation: Ninhydrin assay, Bradford assay, BCA (Bicinchoninic acid) assay, Pierce 660, Biuret assay, and Lowry assay.…”

Impact of Invasive Plant Species on Ecosystems, Biodiversity Loss and Their Potential Industrial Applications

“…It was established that the recovered amount of protein could be influenced by the applied extraction method. (Iyer et al, 2022). These species can also be important in the pharmaceutical industry, having applications in traditional medicine for treating asthma, epilepsy, bleeding (Li et al, 2021) or various sexually transmitted diseases (Maema et al, 2019).…”