Optimization of Enzyme-assisted Revalorization of Sweet Lime (Citrus limetta Risso) Peel into Phenolic Antioxidants

Abstract

Enzymatic treatment was used to induce liberation of antioxidant phenolics from under-utilized sweet lime peel (CLP). Small rotatable central composite design (SRCCD) was selected to optimize the conditions of enzymatic processing, i.e., enzyme concentration (2 to 5%), pH (5 to 8), temperature (30 to 75 °C), and incubation time (30 to 120 min). The morphological characterization of enzymatically hydrolyzed CLP was performed using field emission scanning electron microscopy (FESEM). Extracts obtained under suitable conditions were characterized for their phenolic profile by use of reverse-phase high-performance liquid chromatography coupled with a diode array detector (RP-HPLC-DAD) and evaluated for in vitro antioxidant activities. The observed results revealed that optimum enzymatic pre-treatment doubled the recovery of phenolic antioxidants with maximum Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging potential (IC50). The observed results indicate that enzyme-assisted extraction might be a green choice to revalorize agro-processing residues.

Enzymatic debittering of Citrus reticulata (Kinnow) pulp residue and its utilization for the preparation of vermicelli

“…Significant morphological changes in terms of clear fibers are visible in kinnow pulp residue after enzymatic treatment with respect to untreated samples of kinnow residue. This might be due to massive swelling that makes cells got break down easily after enzymatic treatment leads to release of phenolic compounds (Mushtaq et al., 2014). SEM images confirmed the presence of fibers in kinnow pulp residue.…”

Enzyme-assisted supercritical fluid extraction of phenolic antioxidants from pomegranate peel

“…The use of enzymes have already been investigated during solvent and aqueous extraction as well as in cold pressing to improve the extraction of polysaccharides [11], edible and non-edible oils [12] proteins [13] and phenolics [14] but as such rarely attempt have been made to utilize enzyme in a highly selective supercritical fluid extraction.…”

Antimutagenic and Antioxidant Potential of Aqueous and Acidified Methanol Extracts From Citrus Limonum Fruit Residues

“…The reason might be the presence of covalent linkage between phenolics (bound phenolics) and cell wall constituents. Conventionally, organic solvents such as methanol and ethanol are known to be efficient for the extraction of free phenolics (entrapped) but these solvents are often unable to extract and liberate citrus bound phenolics (more than 20 % phenolics are in bound form) from the well-organized cellulosic cell wall structure further fortified by lignin and in certain cases shielded by pectin 10 . During the present study, therefore, a simple acid hydrolysis based process was applied to facilitate the liberation of bound phenolics from citrus fruit residues (peel and pulp biomass) during aqueous methanol extraction.…”