Mechanical properties and microstructure of potato peels

Figures & data

Figure 1. Two varieties of potatoes.

Figure 2. Friction test and its principle.

Figure 3. Sampling direction of potato peel for static friction test.

Figure 4. Sampling direction and tensile sample of potato.

Figure 5. Tensile and tear test with their samples.

Figure 6. Trousers tearing test.

Figure 7. Static friction coefficient of potato peel.

Figure 8. Stress–strain curve of patato peel tensile test(Yangyu 4).

Figure 9. Stress–strain curve of patato peel tensile test(Helan 14).

Figure 10. Fracture samples of potato peels.

Table 1. Mean value and standard error of mechanical properties of potato peels under tensile loading.

Breed	Parts	Maximum load/N	Tensile strength (MPa)	Modulus of elasticity (MPa)	Failure strain (%)
Yangyu 4	Longitudinal	5.41 ± 0.635	1.41 ± 0.223	0.18 ± 0.025	4.474
	Transverse	6.07 ± 1.146	1.35 ± 0.253	0.24 ± 0.087	4.135
Helan 14	Longitudinal	4.84 ± 0.32	1.33 ± 0.251	0.14 ± 0.087	2.752
	Transverse	5.22 ± 0.26	1.22 ± 0.196	0.18 ± 0.041	2.409

Figure 11. Force–deformation curve of tear test of Yangyu 4 peel.

Figure 12. Force–deformation curve of tear test of Helan14 peel.

Table 2. Mean value and standard error of torn strength of potato peels.

	Tear force/N				Tear strength/kN·m-1
Sample number	Yangyu 4 longitude sampling	Yangyu4 transverse sampling	Helan 14 longitude sampling	Helan14 transverse sampling	Yangyu 4 longitude sampling	Yangyu 4 transverse sampling	Helan 14 longitude sampling	Helan14 transverse sampling
1	0.0526	0.0887	0.1084	0.0698	0.1756	0.296327	0.3261	0.2098
2	0.0791	0.0977	0.093	0.0769	0.2342	0.2943	0.2325	0.2471
3	0.0683	0.0905	0.0945	0.0893	0.2701	0.28	0.18	0.2457
4	0.0808	0.0971	0.0614	0.0809	0.2184	0.2994	0.2172	0.2527
5	0.0874	0.0969	0.0531	0.0960	0.2317	0.2748	0.2668	0.2263
6	0.0626	0.0943	0.0961	0.0882	0.2078	0.2865	0.227	0.1976
7	0.0594	0.0936	0.0922	0.0948	0.2214	0.2721	0.191	0.2102
8	0.0753	0.0927	0.066	0.0885	0.213	0.2764	0.2043	0.1982
9	0.06	0.09	0.061	0.0825	0.184	0.29	0.1653	0.2755
10	0.0753	0.0914	0.067	0.0844	0.272	0.2863	0.173	0.2234
11	0.08	0.089	0.0813	0.0753	0.232	0.275	0.2213	0.2755
12	0.0861	0.0952	0.0832	0.0903	0.266	0.2837	0.1772	0.2036
$\bar{X}\pm SD$	0.07 ± 0.01	0.094 ± 0.004	0.08 ± 0.018	0.085 ± 0.008	0.232 ± 0.028	0.284 ± 0.009	0.215 ± 0.046	0.232 ± 0.029

Figure 13. FESEM micrographs of the potato epidermis surface.

Figure 14. Spherical micro-convex structure in the similar-grain gird structures.

Figure 15. Cross-section microstructure of potato peels (Tensile).

Figure 16. Cross-section microstructure of potato peels (Tear).