Effect of Tannin-Binding Agents (Polyethylene Glycol and Polyvinylpyrrolidone) Supplementation on In Vitro Gas Production Kinetics of Some Grape Yield Byproducts

Table 3

Statistical comparison in grape yield byproducts for gas production volume (mL/g DM).

Treatments	Incubation times (h)
	2	4	6	8	12	16	24	36	48
Control
DGB	32.7^b	77.5^b	112.7^b	139.1^b	161.6^b	182.5^b	209.2^b	234.5^b	243.4^b
GP	39.2^a	89.1^a	127.8^a	157.7^a	188.8^a	206.3^a	231.7^a	260.3^a	269.8^a
RW	33.1^b	73.8^c	101.0^c	118.7^c	141.8^c	156.6^c	180.9^c	203.2^c	208.7^c
SEM	0.71	0.78	0.979	1.366	1.76	1.749	2.425	3.187	3.613
Byproducts + PEG
DGB	9.8^a	58.4^a	114.8^a	146.9^b	182.5^b	212.3^b	241.8^b	269.2^b	286.5^b
GP	7.6^a	56.2^a	119.1^a	166.7^a	208.6^a	242.0^a	277.8^a	312.5^a	331.1^a
RW	12.7^a	62.0^a	109.6^a	134.3^c	158.4^c	180.3^c	204.4^c	229.4^c	247.1^c
SEM	1.97	3.09	2.739	3.072	4.132	4.651	5.198	4.599	4.293
Byproducts + PVP
DGB	6.9^a	47.8^b	103.3^b	136.3^b	165.6^b	189.9^b	218.3^b	234.5^b	264.1^b
GP	9.4^a	51.3^ab	115.5^a	163.6^a	205.4^a	239.8^a	276.5^a	310.5^a	327.8^a
RW	9.8^a	54.4^a	104.6^b	132.8^b	159.9^b	182.3^b	206.5^b	229.7^b	247.9^b
SEM	2.06	1.60	1.857	3.081	3.427	4.636	5.015	5.017	5.064

GP: grape pomace, RW: raisin waste, and DGB: dried grape pomace.
^a,b,cWithin a column, means without a common superscript letter differ (𝑃<0.05).