Preparation of biodegradable foam from walnut shells treated by subcritical water

Yang, Wei; Shimizu, Ichiro; Ono, Tsutomu; Kimura, Yukitaka

doi:10.1002/jctb.4451

Cited by 15 publications

(7 citation statements)

References 35 publications

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“…A great amount of walnut shell is available after fruit processing in walnut kernel production centers, yet only a limited amount has been used in industry. 59 In fact, most of it is discarded as waste material or used as fuel for burning applications. 44 But this causes pollution of the environment, and it also has a low utility value.…”

Section: Walnut Shellmentioning

confidence: 99%

“…Various methods have been suggested for the hydrolysis of cellulose and hemicellulose in wood biomass as a means of producing carbohydrates, which are good sources for the production of bioethanol. 59 Another effective method for the utilization of walnut shells is the production of charcoal and activated carbon by executing pyrolysis. 67 During the production of charcoal, the generated gases are usually discharged into the air.…”

Section: Walnut Shellmentioning

confidence: 99%

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

Jahanban-Esfahlan

Amarowicz

2018

RSC Adv.

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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 ).

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Section: Walnut Shellmentioning

confidence: 99%

Section: Walnut Shellmentioning

confidence: 99%

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

Jahanban-Esfahlan

Amarowicz

2018

RSC Adv.

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“…Fruit growth and development are a major research interest (Pinney and Polito, 1983;Wu et al, 2009) as well as the composition and nutritional value of the seed (Fukuda et al, 2003;Kornsteiner et al, 2006;Zhang et al, 2009;Martinez et al, 2010). In recent years, the walnut shell has also been studied due to its potential for the production of bioethanol (Yang et al, 2015;Lancefield et al, 2017), pyroligneous acid (Jahanban-Esfahlan and Amarowicz, 2018), charcoal and activated carbon (Xie et al, 2013) and "nutty carbon, " which is used for Na-ion battery anodes (Wahid et al, 2017). For novel applications and material development, fundamental knowledge of the structure as well as the chemistry of the shell is needed.…”

Section: Introductionmentioning

confidence: 99%

From the Soft to the Hard: Changes in Microchemistry During Cell Wall Maturation of Walnut Shells

et al. 2020

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The walnut shell is a hard and protective layer that provides an essential barrier between the seed and its environment. The shell is based on only one unit cell type: the polylobate sclerenchyma cell. For a better understanding of the interlocked walnut shell tissue, we investigate the structural and compositional changes during the development of the shell from the soft to the hard state. Structural changes at the macro level are explored by X-ray tomography and on the cell and cell wall level various microscopic techniques are applied. Walnut shell development takes place beneath the outer green husk, which protects and delivers components during the development of the walnut. The cells toward this outer green husk have the thickest and most lignified cell walls. With maturation secondary cell wall thickening takes place and the amount of all cell wall components (cellulose, hemicelluloses and especially lignin) is increased as revealed by FTIR microscopy. Focusing on the cell wall level, Raman imaging showed that lignin is deposited first into the pectin network between the cells and cell corners, at the very beginning of secondary cell wall formation. Furthermore, Raman imaging of fluorescence visualized numerous pits as a network of channels, connecting all the interlocked polylobate walnut shells. In the final mature stage, fluorescence increased throughout the cell wall and a fluorescent layer was detected toward the lumen in the inner part. This accumulation of aromatic components is reminiscent of heartwood formation of trees and is suggested to improve protection properties of the mature walnut shell. Understanding the walnut shell and its development will inspire biomimetic material design and packaging concepts, but is also important for waste valorization, considering that walnuts are the most widespread tree nuts in the world.

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“…The residue after hydrolysis is rich in cellulose and lignin, which can be further utilised. Yang et al [5] reported that the optimal conditions for the recovery of carbohydrates (about 400 mg TCH/g walnut shells) from walnut shells with subcritical water are 200 • C and 15 min. The residue from the walnut shells was used to produce a biodegradable foam by mixing it with corn starch.…”

Section: Total Carbohydrates Contentmentioning

confidence: 99%

“…The total global production of pistachios and walnuts (in-shell) in 2022/2023 is estimated to be 747.31 thousand tons [2] and 2.6 million tons [3], respectively. The shell of walnuts consists of 22.2-30.2% hemicellulose, 25.5-27.9% cellulose and 39.1-52.3% lignin [4,5], while the shell of pistachios consists of 20-32% hemicellulose, 30-55% cellulose and 12-38% lignin [6,7]. Usually agricultural biomass waste (walnut and pistachio shells) is incinerated to generate heat.…”

Section: Introductionmentioning

confidence: 99%

The Conversion of Pistachio and Walnut Shell Waste into Valuable Components with Subcritical Water

Čolnik,

Irgolič,

Perva

et al. 2024

Processes

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Pistachio and walnut shells accumulate in large quantities as waste during food processing and represent a promising lignocellulosic biomass for the extraction of valuable components. Subcritical water technology was used as an environmentally friendly technique to study the extraction of active ingredients and other valuable degradation products from walnut and pistachio waste. Subcritical water extraction (SWE) was carried out under different process conditions (temperature (150–300 °C) and short reaction times (15–60 min)) and compared with conventional extraction using different organic solvents (acetone, 50% acetone and ethanol). The extracts obtained from pistachio and walnut shell waste are rich in various bioactive and valuable components. The highest contents of total phenols (127.08 mg GA/g extract at 300 °C for 15 min, from walnut shells), total flavonoids (10.18 mg QU/g extract at 200 °C for 60 min, from pistachio shells), total carbohydrates (602.14 mg TCH/g extract at 200 °C for 60 min, from walnut shells) and antioxidant activity (91% at 300 °C, for 60 min, from pistachio shells) were determined when the extracts were obtained via subcritical water. High contents of total phenols (up to 86.17 mg GA/g extract) were also determined in the conventional extracts obtained with ethanol. Using the HPLC method, sugars and their valuable derivatives were determined in the extracts, with glucose, fructose, furfurals (5-hydroxymethylfurfural (5-HMF) and furfural) and levulinic acid being the most abundant in the extracts obtained by subcritical water. The results show that subcritical water technology enables better exploitation of biowaste materials than conventional extraction methods with organic solvents, as it provides a higher yields of bioactive components such as phenolic compounds and thus extracts with high antioxidant activity, while at the same time producing degradation products that are valuable secondary raw materials.

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Preparation of biodegradable foam from walnut shells treated by subcritical water

Cited by 15 publications

References 35 publications

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

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

From the Soft to the Hard: Changes in Microchemistry During Cell Wall Maturation of Walnut Shells

The Conversion of Pistachio and Walnut Shell Waste into Valuable Components with Subcritical Water

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