Table 3. Changes in pH and total polyphenol content of fermented milk during RLED-assisted fermentation and subsequent refrigerated storage

pH
Treatment	Fermentation (37℃, 72 h)				Refrigerated storage (4℃)
Treatment	Day 0	Day 1	Day 2	Day 3	Day 6	Day 10
Darkness	6.99±0.00^a	4.10±0.02^c	3.74±0.03ᵉ	3.58±0.01ᵍʰ	3.60±0.05ᵍ	3.52±0.02ʰ
RLED	6.99±0.00^a	4.25±0.01^b	3.83±0.02ᵈ	3.66±0.01ᶠ	3.57±0.01ᵍʰ	3.60±0.00ᵍ

Total polyphenol content (μg TAE/100 g)
Treatment	Fermentation (37℃, 72 h)				Refrigerated storage (4℃)
Treatment	Day 0	Day 1	Day 2	Day 3	Day 6	Day 10
Darkness	28.83±1.42^a	11.10±0.26^bc	11.87±0.23^b	11.26±0.80^bc	11.81±0.14^b	11.88±0.26^b
RLED	28.83±1.42^a	10.22±0.16^c	11.39±0.22^bc	11.83±0.35^b	12.26±0.52^b	11.62±0.25^b

Samples were fermented at 37℃ under dark or red light-emitting diode (RLED) conditions for 3 days and subsequently stored at 4℃ in darkness until day 10. Values are presented as mean±SD (n=3). Different letters within each parameter indicate significant differences among treatment–time combinations (p<0.05) according to Tukey's HSD test following one-way ANOVA. TAE, tannic acid equivalents.