Table 2.

Techniques used in the assessment of prebiotic efficacy.

Assessment Type	Techniques	Phases	Types of System	Type of Models	Conditions of Assessment						Samples to Be Evaluated	References
					Time (h)	pH	Temp (°C)	Detector	Salts	Enzymes
Digestion of prebiotics	in vitro	Oral			5	7	37		NaCl	Alpha-amylase		[104]
		Gastric			2	2.5	37			Pepsin, Gastric Lipase		[105]
		Intestinal			2	6	37			Chymotrypsin, Trypsin, Colipase and Pancreatic Lipase		[106]
	In vivo			Animals	672		18–29				Fecal sample	[106,107]
				Human clinical	336						Undigested prebiotics	[106]
Fermentation of prebiotics	In vitro		Batch culture		24	6.5	37		Na2HPO4, NaH2PO4		Fecal sample	[22,108]
			Continuous culture	Single staged, multi-staged	16	6.8	37				Fecal sample	[109]
			Artificial gut	TIM	20	6	37				Fecal sample	[110]
				SHIME	24–72	6.5 7.0 7.5	37		Na2Co3		Fecal sample	[111]
	In vivo			Animals	672		22–29				Fecal sample	[112,113]
				Human Clinical							Fecal sample or Breathed air	[113]
Analysis of Prebiotics	SCFAs Analysis		HPLC		1	2.5	40	UV-Vis				[106,114]
			GC		0.5		250	FID				[106]
			HILIC		0.5		35	ELSD				[106,115]
			LC–ESI–MS.		0.5		35	DAD				[115,116]
	Gut Microbiota Enumeration	Culturing										[117]
		Molecular Methods		RT-PCR								[117]
				qPCR								[118]
				DGGE								[106]
				T-RFLP								[119]
				DNA Microarray								[106]
				16s rRNA								[106,120]
				Pyrosequencing								[106,120]

SCFAs—short-chain fatty acids, SHIME—simulator of the human intestinal microbial ecosystem, TIM—The Netherlands Organization for Applied Scientific Research intestinal model, FID—flame ionization detector, ELSD—evaporative light-scattering detector, DAD—diode array detector, T-RFLP—terminal restriction fragment length polymorphism, DGGE—denaturing gradient gel electrophoresis, RT-PCR—real-time polymerase chain reaction, qPCR—quantitative polymerase chain reaction, rRNA—ribosomal ribonucleic acid, HPLC—High-performance liquid chromatography, HILIC—Hydrophilic interaction liquid chromatography.