Changes in Lignin Content and Activity of Related Enzymes in the Endocarp During the Walnut Shell Development Period

Zhao, Shugang; Wen, Jing; Wang, Hongxia; Zhang, Zhihua; Xi-bo, LI

doi:10.1016/j.hpj.2016.08.003

Cited by 42 publications

(24 citation statements)

References 4 publications

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“…Furthermore, the lignin content is also correlated to the mechanical strength and thickness of the walnut shell [29]. Due to this particular quality, it is very important to crack and loosen the dense structure in order for the solvent to penetrate the cell to extract the phenolic compounds.…”

Section: Surface Structure Of the Walnut Shellmentioning

confidence: 99%

“…Moreover, in Figure 3(D), many more porous particles appeared as the structure was ground more and screened through 100 mesh (<0.150 mm). More phenolic compounds are stored in dense structures containing high lignin and cellulose, giving a positive correlation between phenolic content and the amount of lignin and cellulose [29].…”

Section: Sem Analysis Of the Surface Characteristics Of The Walnut Shmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Ultrasound-Assisted Extraction of Phenolic Compounds on the Characteristics of Walnut Shells

Han¹,

Wang²,

Rakita³

et al. 2018

FNS

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Walnuts are one of nature's more waste-heavy products. 67% of the nut is shell and husk, low value by-products that are rich in phenolic compounds. The phenolic compounds extracted from walnut shells are potentially good natural sources of antioxidants for the food and pharmaceutical industries. In this study, phenolic compounds were extracted using an ultrasonic bath, an ultrasonic probe and a standard shaking method. The extraction yield achieved with an ultrasonic probe was 51.2 mg GAE/g DW, two times higher than both the shaking method and the ultrasonic bath method which were 20.6 mg GAE/g DW and 25.8 mg GAE/g DW, respectively. Phenolic extraction was further improved by a size reduction of the walnut shells. The best extraction yield of 52.8 mg GAE/g DW was attained when the particle size was between 45-100 mesh. The ultrasonic probe treatment is the best method for extraction of phenolic compounds from walnut shells. Scanning electron microscopy (SEM) imaging indicated that the ultrasonic probe treatment could better rupture the hard structure of the cells, increasing the penetration of solvents and thus the extraction yield.

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Section: Surface Structure Of the Walnut Shellmentioning

confidence: 99%

Section: Sem Analysis Of the Surface Characteristics Of The Walnut Shmentioning

confidence: 99%

Effect of Ultrasound-Assisted Extraction of Phenolic Compounds on the Characteristics of Walnut Shells

Han¹,

Wang²,

Rakita³

et al. 2018

FNS

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“…Sclereids, typified by thick secondary walls, exist in the shells of nuts, bark, pith, leaves, and sarcocarps of pear fruit, and in the secondary xylem of certain taxa (Fahn, 1967;Lee et al, 2006). Previous studies have indicated that walnut shell is composed of sclereids (Zhao et al, 2007(Zhao et al, , 2016, which are differentiated from the parenchymal cells in the endocarp (Xiao et al, 1998). Zhang et al (2014aZhang et al ( , 2014b assessed walnut shells using scanning electron microscopy, and the results showed that the shell consisted of two layers according to the different patterns of cell fracture.…”

Section: Discussionmentioning

confidence: 99%

“…Extraction of phenolic compounds. The total phenolic content was determined using the Folin-Ciocalteu colorimetric method (Zhao et al, 2016). Briefly, each sample (0.1 g) was thoroughly mixed with 5 mL of Folin-Ciocalteu reagent (diluted 10-fold), followed by the addition of 8 mL sodium carbonate (10%) solution.…”

Section: Methodsmentioning

confidence: 99%

“…The pattern of shell-hardening is basipetal in the longitudinal plane and centripetal in the transverse plane. The first cells to become sclerified are those at the micropylar end (the upper part of the fruit), with sclerification occurring in early June (Pinney and Polito, 1983;Zhao et al, 2016). Sclerification proceeds basipetally from this point, with the cells along the seal lines becoming sclerified rapidly.…”

mentioning

confidence: 99%

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The Relationship among the Structural, Cellular, and Physical Properties of Walnut Shells

Zhao¹,

Niu²,

Yun³

et al. 2019

horts

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The role of the walnut (Juglans regia L.) shell in nut development, transportation, cleaning, and storage is often ignored. The shell suture seal and thickness are directly associated with kernel characteristics. In the present study, shell differentiation and microstructure were observed with an optical microscope using paraffin-sectioning and cryosectioning. The results showed that the parenchymal cells of the endocarp began to differentiate into sclerenchymal cells from 49 d after flowering (DAF), and the entire process continued until fruit maturation. The mature shell consists of three parts, including the sclereid layer (L1), sclerenchymal cell layer (L2), and shrunken cell layer (L3), from the outside to the inside. The shell thickness, suture seal grade, and mechanical strength were evaluated, as well as the lignin, cellulose, and phenolic compounds of the shell. Suture seal grade was positively correlated with lignin content, shell thickness, and L1 thickness and negatively correlated with shell cell diameter. Similarly, the mechanical strength of the shell was positively correlated with lignin content and L1 thickness. 'Qingxing' fruits were subjected to two treatments, namely, 30% shading and 70% shading, from 10 d after anthesis to maturity, with no shading used as control. After harvesting in September, nutshell sections showed thinner shells, with decreased contents of lignin and polyphenols, obtained under shaded conditions, and two of the three parts of the shell changed dramatically. The thinning of L1 and thickening of L3 eventually led to a thinner shell. The aim of this study was to evaluate the relationship among the shell structure, cellular components, and physical properties and provide a theoretical basis for cultivar breeding, rational planting density, and regulation of shell development.

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Allometry and volumes in a nutshell: Analyzing walnut morphology using three‐dimensional X‐ray computed tomography

Amézquita,

Quigley,

Brown

et al. 2024

The Plant Phenome Journal

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Persian walnuts (Juglans regia L.) are the second most produced and consumed tree nut, with over 2.6 million metric tons produced in the 2022–2023 harvest cycle alone. The United States is the second largest producer, accounting for 25% of the total global supply. Nonetheless, producers face an ever‐growing demand in a more uncertain climate landscape, which requires effective and efficient walnut selection and breeding of new cultivars with increased kernel content and easy‐to‐open shells. Past and current efforts select for these traits using hand‐held calipers and eye‐based evaluations. Yet there is plenty of morphology that meets the eye but goes unmeasured, such as the volume of inner air or the convexity of the kernel. Here, we study the shape of walnut fruits based on X‐ray computed tomography three‐dimensional reconstructions. We compute 49 different morphological phenotypes for 1264 individual nuts comprising 149 accessions. These phenotypes are complemented by traits of breeding interest such as ease of kernel removal and kernel‐to‐nut weight ratio. Through allometric relationships, relative growth of one tissue to another, we identify possible biophysical constraints at play during development. We explore multiple correlations between all morphological and commercial traits and identify which morphological traits can explain the most variability of commercial traits. We show that using only volume‐ and thickness‐based traits, especially inner air content, we can successfully encode several of the commercial traits.

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Changes in Lignin Content and Activity of Related Enzymes in the Endocarp During the Walnut Shell Development Period

Cited by 42 publications

References 4 publications

Effect of Ultrasound-Assisted Extraction of Phenolic Compounds on the Characteristics of Walnut Shells

Effect of Ultrasound-Assisted Extraction of Phenolic Compounds on the Characteristics of Walnut Shells

The Relationship among the Structural, Cellular, and Physical Properties of Walnut Shells

Allometry and volumes in a nutshell: Analyzing walnut morphology using three‐dimensional X‐ray computed tomography

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