Chemical Traits of Fermented Alfalfa Brown Juice: Its Implications on Physiological, Biochemical, Anatomical, and Growth Parameters of Celosia

Abstract

Brown juice is a byproduct of fractionated green biomass during leaf protein isolation. It represents approximately 45%–50% of the total pressed fresh biomass. Disposal of brown juice is a serious issue in leaf protein production due to its high biological oxygen demand and carbohydrates content. The current study aimed to find a possible potential use of brown juice. Therefore, chemical and biochemical properties of brown juice—derived from alfalfa green biomass—were determined before and after fermentation by lactic acid bacteria. Additionally, the growth stimulation potential of fermented brown juice on plumed cockscomb (Celosia argantea var. plumose ‘Arrabona’) plants were tested. Celosia seedlings were sprayed at different rates of fermented brown juice (i.e., 0.5%, 1%, 2.5%, 5%, and 10%) and tap water was applied as control. The results revealed that lactic acid bacteria successfully enhanced the stabilization of brown juice via reducing sugars content and increasing organic acids content. After fermentation, contents of glucose monomers were 15 times lower; while concentrations of lactic and acetic acids increased by 7- and 10-fold, respectively. This caused a reduction in the pH of fermented brown juice by 13.9%. Treating Celosia plants at lower rates of fermented brown juice (up to 1.0%) significantly induced their growth dynamics and antioxidant capacity. Higher values of vegetative parameters were measured in treated plants compared to control. The brown juice treatments caused significant changes in histological parameters as well. The activity of catalase and peroxidase increased in plants that received fermented brown juice especially at low rates. Moreover, an increase in water-soluble protein and phenol was measured in different tissues of plants sprayed with fermented brown juice. Malondialdehyde content was lowered in treated plants compared to control. Fermented brown juice at high rates slightly reduced the amount of photosynthetic pigments; however, this reduction was not reported for low rates of fermented brown juice. These results surely illustrate the potential use of fermented alfalfa brown juice as a growth stimulator for crops particularly at rates below 2.5%.

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

“…Depending on the specific processing techniques, the color of brown juice may vary from yellowish-brown to dark brown or green. 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).…”

Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications

“…Bákonyi et al [31] and Kisvarga et al [32] reported that alfalfa brown juice could be considered a potential growth stimulator. In their studies, Celosia seedlings where sprayed at five increasing rates of fermented brown juice (0.5%, 1.0%, 1.5%, 2.0% or 2.5%), while basil was sprayed at three different increasing doses (0.5%, 1.0% or 2.5%).…”

Raw and Fermented Alfalfa Brown Juice Induces Changes in the Germination and Development of French Marigold (Tagetes patula L.) Plants

“…A recently-developed and novel technology enables the production of large amounts of an environmentally-friendly alfalfa-based organic biostimulant called brown juice (BJ), which is a by-product of leaf protein concentrate (LPC) [2]. The pH of fresh BJ varies between 5 and6, and it contains several biologically-active components, including phenols, amino acids, macro-and microelements, carbohydrates (40%), and nitrogen (3%) on a dry mass basis [3][4][5]. Due to its high sugar content, fresh BJ spoils within a week of storage at room temperature.…”