Table 3. Estimated discoloration preventing efficiency (DPE) of UV-protective coating on bamboo outer surfaces based on regression analysis results

Radiation time (h)	Estimated dE*				DPE (%)
	Hot-air dried		Heat treated		Hot-air dried	Heat treated
	Uncoated	Coated	Uncoated	Coated
21	6.76	4.63	5.76	4.09	31.48	29.02
42	10.86	8.02	9.53	7.26	26.17	23.80
63	12.93	10.17	11.88	10.08	21.36	15.20
72	13.20	10.71	12.46	11.18	18.82	10.30

UV: ultraviolet.