Details
| Original language | English |
|---|---|
| Pages (from-to) | 485-489 |
| Number of pages | 5 |
| Journal | Journal of the American Society for Horticultural Science |
| Volume | 141 |
| Issue number | 5 |
| Publication status | Published - 1 Sept 2016 |
Abstract
Rain cracking of sweet cherry fruit (Prunus avium L.) is said to occur when the volume increase associated with water uptake, extends the fruit skin beyond its upper mechanical limits. Biaxial tensile tests recorded fracture strains (εfracture) in the range 0.17 to 0.22 mm2·mm–2 (equivalent to 17% to 22%). In these tests, an excised skin segment is pressurized from its inner surface and the resulting two-dimensional strain is quantified. In contrast, the skins of fruit incubated in water in classical immersion assays are fractured at εfracture values in the range 0.003 to 0.01 mm2·mm–2 (equivalent to 0.3% to 1%)—these values are one to two orders of magnitude lower than those recorded in the biaxial tensile tests. The markedly lower time to fracture (tfracture) in the biaxial tensile test may account for this discrepancy. The objective of our study was to quantify the effect of εfracture on the mechanical properties of excised fruit skins. The εfracture was varied by changing the rate of increase in pressure (prate) and hence, the rate of strain (εrate) in biaxial tensile tests. A longer tfracture resulted in a lower pressure at fracture (pfracture) and a lower εfracture indicating weaker skins. However, a 5-fold difference in εfracture remained between the biaxial tensile test of excised fruit skin and an immersion assay with intact fruit. Also, the percentage of epidermal cells fracturing along their anticlinal cell walls differed. It was highest in the immersion assay (94.1% ± 0.6%) followed by the long tfracture (75.3% ± 4.7%) and the short tfracture (57.3% ± 5.5%) in the biaxial tensile test. This indicates that the effect of water uptake on cracking extends beyond a mere increase in fruit skin strain resulting from a fruit volume increase. Instead, themuch lower εfracture in the immersion assay indicates amuchweaker skin—some other unidentified factor(s) are at work.
Keywords
- Biomechanics, Cracking, Mechanical properties, Prunus avium, Rheology, Skin
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Genetics
- Agricultural and Biological Sciences(all)
- Horticulture
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In: Journal of the American Society for Horticultural Science, Vol. 141, No. 5, 01.09.2016, p. 485-489.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Time to fracture and fracture strain are negatively related in sweet cherry fruit skin
AU - Brüggenwirth, Martin
AU - Knoche, Moritz
PY - 2016/9/1
Y1 - 2016/9/1
N2 - Rain cracking of sweet cherry fruit (Prunus avium L.) is said to occur when the volume increase associated with water uptake, extends the fruit skin beyond its upper mechanical limits. Biaxial tensile tests recorded fracture strains (εfracture) in the range 0.17 to 0.22 mm2·mm–2 (equivalent to 17% to 22%). In these tests, an excised skin segment is pressurized from its inner surface and the resulting two-dimensional strain is quantified. In contrast, the skins of fruit incubated in water in classical immersion assays are fractured at εfracture values in the range 0.003 to 0.01 mm2·mm–2 (equivalent to 0.3% to 1%)—these values are one to two orders of magnitude lower than those recorded in the biaxial tensile tests. The markedly lower time to fracture (tfracture) in the biaxial tensile test may account for this discrepancy. The objective of our study was to quantify the effect of εfracture on the mechanical properties of excised fruit skins. The εfracture was varied by changing the rate of increase in pressure (prate) and hence, the rate of strain (εrate) in biaxial tensile tests. A longer tfracture resulted in a lower pressure at fracture (pfracture) and a lower εfracture indicating weaker skins. However, a 5-fold difference in εfracture remained between the biaxial tensile test of excised fruit skin and an immersion assay with intact fruit. Also, the percentage of epidermal cells fracturing along their anticlinal cell walls differed. It was highest in the immersion assay (94.1% ± 0.6%) followed by the long tfracture (75.3% ± 4.7%) and the short tfracture (57.3% ± 5.5%) in the biaxial tensile test. This indicates that the effect of water uptake on cracking extends beyond a mere increase in fruit skin strain resulting from a fruit volume increase. Instead, themuch lower εfracture in the immersion assay indicates amuchweaker skin—some other unidentified factor(s) are at work.
AB - Rain cracking of sweet cherry fruit (Prunus avium L.) is said to occur when the volume increase associated with water uptake, extends the fruit skin beyond its upper mechanical limits. Biaxial tensile tests recorded fracture strains (εfracture) in the range 0.17 to 0.22 mm2·mm–2 (equivalent to 17% to 22%). In these tests, an excised skin segment is pressurized from its inner surface and the resulting two-dimensional strain is quantified. In contrast, the skins of fruit incubated in water in classical immersion assays are fractured at εfracture values in the range 0.003 to 0.01 mm2·mm–2 (equivalent to 0.3% to 1%)—these values are one to two orders of magnitude lower than those recorded in the biaxial tensile tests. The markedly lower time to fracture (tfracture) in the biaxial tensile test may account for this discrepancy. The objective of our study was to quantify the effect of εfracture on the mechanical properties of excised fruit skins. The εfracture was varied by changing the rate of increase in pressure (prate) and hence, the rate of strain (εrate) in biaxial tensile tests. A longer tfracture resulted in a lower pressure at fracture (pfracture) and a lower εfracture indicating weaker skins. However, a 5-fold difference in εfracture remained between the biaxial tensile test of excised fruit skin and an immersion assay with intact fruit. Also, the percentage of epidermal cells fracturing along their anticlinal cell walls differed. It was highest in the immersion assay (94.1% ± 0.6%) followed by the long tfracture (75.3% ± 4.7%) and the short tfracture (57.3% ± 5.5%) in the biaxial tensile test. This indicates that the effect of water uptake on cracking extends beyond a mere increase in fruit skin strain resulting from a fruit volume increase. Instead, themuch lower εfracture in the immersion assay indicates amuchweaker skin—some other unidentified factor(s) are at work.
KW - Biomechanics
KW - Cracking
KW - Mechanical properties
KW - Prunus avium
KW - Rheology
KW - Skin
UR - http://www.scopus.com/inward/record.url?scp=84990854067&partnerID=8YFLogxK
U2 - 10.21273/JASHS03810-16
DO - 10.21273/JASHS03810-16
M3 - Article
AN - SCOPUS:84990854067
VL - 141
SP - 485
EP - 489
JO - Journal of the American Society for Horticultural Science
JF - Journal of the American Society for Horticultural Science
SN - 0003-1062
IS - 5
ER -