Refining high-quality leaf protein and valuable co-products from green biomass of Jerusalem artichoke (Helianthus tuberosus L.) for sustainable protein supply

Abstract

The present study evaluates the green biomass of Jerusalem artichoke (JA) as an alternative green protein. A leaf protein concentrate (LPC) was prepared from leafy shoots using biotechnological methods. Seven clones were compared to assess the importance of the genetic basis of JA, and alfalfa served as the control. The LPC content of JA was an average 39 g kg −1 of fresh biomass, while that of alfalfa was 32 g kg −1. The JA can produce up to 936 kg of protein ha −1 year −1 without fertilization under rainfed conditions. The crude protein content of the LPC varied from 24.2 to 31.4 m/m%, depending on clones and harvesting time, which was comparable to that of alfalfa LPC (~32.3%). The amino acid profile of the LPC of JA, particularly of the essential amino acids, was similar to alfalfa and soybean. In addition, our results confirmed that the polyunsaturated fatty acid (PUFA) content varied between 64 and 68% in the LPC fraction, regardless of the clone that was used, with linoleic acid and linolenic acid being the predominant PUFAs. In addition, unlike alfalfa, the content of arachidonic acid was 0.5% in the JA LPC. The tuber yield was significantly reduced because of the repeated harvesting of the shoot parts; however, the tubers obtained were sufficient to regenerate the plantation in the subsequent year, thus ensuring the renewable ability and sustainability of the green biomass of JA.

Uptake Dynamics of Ionic and Elemental Selenium Forms and Their Metabolism in Multiple-Harvested Alfalfa (Medicago sativa L.)

“…Second reason is that alfalfa has a great importance as an alternative source of protein alongside soybean in the continental climate zone. Beyond traditional uses such as hay production, these days alfalfa is considered as a promising crop in the novel green biorefinery concept [ 32 , 33 ]. Green biorefinery processes convert the raw green biomass into a range of marketable products including feed, food, chemicals, biofuels, heat (multi-product-system) based on deployment of sustainable zero-waste technologies.…”

“…Similar results were reported in leaf for the same treatment, with higher Se content than the stem, as in the 1st harvest, the total Se content was 643.4 µg g −1 and declined to 58.1 µg g −1 in the 4th harvest ( Figure 1 ). Two reasons could be behind this high rate of Se (VI) uptake in the first two harvests and the low rate in the next consecutive harvests, i.e., 3rd and 4th harvests: (1) the short root system of alfalfa in the first harvests compared to late harvests as the upper layer of soil is more aerated than the deeper one that ensure the existence of Se in form of Se (VI) due to the oxic conditions [ 33 ], and (2) the high dose of applied Se (VI), i.e., 10 mg kg −1 . However, this cannot be referred to the low sulfur soil content since Se (VI) is absorbed through the same transporters as sulfate because the sulfur content in the experimental soil was 220 ± 5.6 mg kg −1 ( Table S3 ) which is much higher than the recommended sulfur soil content 10–20 mg kg −1 [ 34 ].…”

“…On the other hand, in soil that lacks aeration (anoxic), Se (IV), the less mobile and available Se from, is the dominant form, while further reduction of Se (VI) can lead to selenide (2-) and Se 0 forms [ 33 ]. In our experiment, alfalfa root absorbed Se (IV) at a lower rate than Se (VI); 1 mg kg −1 Se (VI) resulted in total stem Se content higher than that of 10 mg kg −1 Se (IV) in the 1st harvest.…”

Sustainable Biorefinery and Production of Alfalfa (Medicago sativa L.)

“…This brown juice can be applied as a bio-organic fertilizer to promote crop growth and as a medium for microbial growth (Shende & Gogle, 2016;Bákonyi et al, 2020). The biorefining process of alfalfa has positive impacts not only on the environment but also on human health, which could be expected using novel protein sources (De Corato et al, 2018;Kaszás et al, 2020).…”

Identification of Bioactive Phytochemicals in Leaf Protein Concentrate of Jerusalem Artichoke (Helianthus tuberosus L.)

“…The fatty acid and lipid contents of JA tubers have been reported by several authors [ 11 , 40 ]; however, little information is available about the fatty acid composition of its leaves and JAPC [ 41 ]. Recently, rapidly growing interest is for PUFAs, because humans and other mammals are incapable of synthesizing omega-6 and omega-3 PUFAs, due to the lack of Δ12 and Δ15 desaturase enzymes, which insert a cis double bond at the n-6 and n-3 positions [ 42 ]. Hence, linolenic and linoleic acids are essential nutrients converted from oleic acid in the endoplasmic reticulum of plant cells.…”