Walnut (Juglans regiaL.) shell pyroligneous acid: chemical constituents and functional applications

Abstract

Upon the processing of different agricultural products, considerable amounts of by-products and biowastes are produced and discarded or burnt as fuel, which are a potential source of valuable compounds. Over the past several decades, plant by-products have been recognized as a source of nutraceutical components, including dietary fibers, phenolics, and many other useful compounds. The walnut is known as an important tree nut. The shell of a walnut is the middle part of the fruit and it is a waste product of walnut processing industries. Recently, pyroligneous acids from the walnut shell have been receiving much-increasing interest because of their excellent antimicrobial and antioxidant activities. Hence, this review deals with the recent scientific literature on walnut shell pyroligneous acids and their chemical composition as well as their functional applications.a Collected at three temperature ranges by GC-MS. b Collected at seven temperature ranges by GC-MS. c 5% NaHCO 3 extract (OA 5 ) and 4% NaOH extract (P 3 ).This journal is a Collected at three temperature ranges by GC-MS. b Collected at seven temperature ranges by GC-MS. c 5% NaHCO 3 extract (OA 5 ) and 4% NaOH extract (P 3 ). Fig. 2 The chemical structures of organic acids identified in walnut shell pyroligneous acids.This journal is a Collected at three temperature ranges by GC-MS. b Collected at seven temperature ranges by GC-MS. c 5% NaHCO 3 extract (OA 5 ) and 4% NaOH extract (P 3 ).22382 | RSC Adv., 2018,8,[22376][22377][22378][22379][22380][22381][22382][22383][22384][22385][22386][22387][22388][22389][22390][22391] This journal is a Collected at three temperature ranges by GC-MS. b Collected at seven temperature ranges by GC-MS. c 5% NaHCO 3 extract (OA 5 ) and 4% NaOH extract (P 3 ).

Phytochemical Screening and Antioxidant Potential of Aqueous Extracts of Millettia laurenti, Lophira alata and Milicia excelsa, Commonly Used in the Cameroonian Pharmacopoeia

“…A weak correlation between the NO radicals scavenging activity of Walnut kernels (Juglans regia L.) and the phenolic content (r 2 = 0.08) as well as the flavonoid content (r 2 = 0.07) was also cited by many studies (2012) [35,36]. However, there is for instance positive correlation between the phenolic contents of Amygdalus communis and the NO radical scavenging activity [37]. This therefore also question the nature of the compounds present in the extracts.…”

Recent advances in the use of walnut (Juglans regia L.) shell as a valuable plant-based bio-sorbent for the removal of hazardous materials

“…In most walnut cultivars, the shell must be cracked mechanically to obtain the meat. 7 The internal portion of the fruit is the kernel or seed, which consumed as the nutritious part of the fruit. 50 Similar to that in other tree nuts such as almonds, the kernel of the walnut is covered by a thin leathery light brown layer called the skin, seed coat, or pellicle.…”

“…In some areas, both shells and husks are burned as fuel for heating purposes, which may cause environmental pollution. 7 The husk and the shell account for more than 60% of the walnut fruit by weight. The shell makes up a considerable percentage of the fruit by weight ($40%) and is available as an abundant and low-cost agricultural by-product in walnut production centres.…”

“…One of the main and recently highlighted applications of WS by-products is the use of processed or unprocessed WS as biosorbent. 7 Accordingly, this review aims to summarize up-to-date developments in the preparation and application of unmodied and modied WS in the form of ACs, as well as chemically modied WS in adsorption procedures for the removal of HMs, dyes, oils, pharmaceuticals and other hazardous substances from aqueous solutions. Additionally, important parameters for obtaining optimal adsorption conditions for different hazardous materials are highlighted.…”

Potential applications of pecan residual biomasses: a review

“…It is important to assign high attention to the reuse of pecan wastes biomasses, thus exploring the potential of these materials for resulting in higher added value to their coproducts. These materials contain high concentrations of cellulose, hemicelluloses and lignin [5]. Also, a range of applications of pecan coproducts is known, especially in the extraction of compounds of interest for use in different fields of application, such as the biofuel production, pharmaceutical and food industries.…”