Whatman no 2 filter paper

The extraction of MCPG was mixed with 70% ethanol at room temperature for 30 min using a magnetic stirrer. A funnel with a Whatman No. 2 filter paper (GE Healthcare Life Sciences, Piscataway, NJ, USA) was loaded onto a Kimble filtering flask to filter the extracted MCPG. Subsequently, the filtrate as the final extract was dried at 105 °C in a hot-air dryer (HB-502M; HanBeak Scientific Co., Bucheon, Republic of Korea) until there was no change in weight. The extraction yield was calculated using the following equation: $$\mathrm{Extraction}\mathrm{yield}(\%)=\frac{\left({\mathrm{W}}_2-{\mathrm{W}}_1\right)}{\mathrm{A}}\times \frac{\mathrm{E}}{{\mathrm{E}}^{\prime }}\times 100$$
W₁: weight of empty aluminum dish (g)
W₂: weight of aluminum dish and solid (g)
A: weight of dried ginseng (g)
E: total volume of extract (mL)
E′: used volume of extract (mL)
The filtrate was concentrated using a rotary vacuum evaporator (N-11, EYELA, Tokyo, Japan). For further analyses, concentrated samples dissolved in distilled water were aliquoted.

A total of 42 plant extracts were originally provided from the Korea Plant Extract Bank at Korea Research Institute of Bioscience and Biotechnology (KRIBB) (Ochang, Chungbuk, Korea) [42 (link)]. The ethanol extracts were prepared based on a previous report [43 (link)]. Briefly, after botanical authentication, the dried plant material was turned into powder using a grinding mill. Next, 100 g of plant powder was extracted in 1000 mL of 0%, 30%, 50%, 70%, and 100% aqueous ethanol solution (v/v) in an occasional shaker at room temperature for 72 h. The extract was then filtered with Whatman No. 2 filter paper (GE Healthcare Life Sciences, Logan, UT, USA) to remove debris, and the filtrate was collected and concentrated in a rotating evaporator at 40–50 °C and lyophilized under reduced pressure. The dried extract was stored in amber flasks at 4 °C, re-suspended with distilled water, and filtered through a 0.22-μm membrane filter (Sartorius, Gottingen, Germany) before the experiments.

The total volatile basic nitrogen (TVBN) value of pork loin samples was determined using Conway’s micro-diffusion method [15 (link)]. Five grams of meat was homogenized with 45 mL of distilled water using a slap-type homogenizer (WS-400, Shanghai Zhisun Equipment Co., Ltd., Shanghai, China) for 180 s. The homogenate was filtered using Whatman No. 2 filter paper (GE Healthcare, Chicago, IL, USA). After filtration, 1 mL of filtrate was placed on the outer side of a Conway dish containing 1 mL of 0.01 N H₃BO₃ mixture, and 100 μL of Conway solution (0.066% methyl red in ethanol: 0.066% bromocresol green in ethanol) was dropped into the inner side of the Conway dish. Next, 1 mL 50% K₂CO₃ was added to the outer side of the dish. The lid of the Conway dish was closed, and the dish was incubated at 37 °C for 2 h in a thermo-hygrostat (IL3-25A, JEIO Tech, Daejeon, Republic of Korea). The TVBN content was determined following the addition of 0.02 N H₂SO₄ to the inner side of the Conway dish. A blank test was performed following the same process without the addition of the homogenized samples. The TVBN value was calculated as follows: $$\mathrm{TVBN} \left(\mathrm{mg}/100 \mathrm{g}\right)=\frac{14.007\times \left(a-b\right)\times f\times 100\times c}{S},$$
where a is the titration volume of the sample (mL), b is the titration volume of the blank (mL), f is the factor of H₂SO₄, S is the weight of the sample, and c is the dilution factor.