Pr 101r

Fresh juice was produced using a juicer (SUPOR SJ30, Shanghai, China) for use in the determination of SSC and TA. SSC was analyzed using a sugar refractometer (Atago PR-101R, Tokyo, Japan) [16 (link)]. TA was measured using an automatic titrator (794 Basic Titrino, Metrohm, Switzerland) and expressed as % citric acid [17 (link)]. pH was determined with a PHS-3E meter (Shanghai Leici Co., Ltd., Shanghai, China) [18 (link)]. MI values were calculated as the SSC/TA ratio.

The soluble solids content was measured by a digital refractometer (Atago PR-101R, Tokyo, Japan). The pH of the wines was monitored by a digital pH meter (pHS-3C, Shanghai Aohaosi Instrument, Shanghai, China). Titratable acidity, alcohol and free SO₂ in wine samples were tested according to the methods of the International Organization of Vine and Wine [18 ], Residual sugar content was assessed using the dinitrosalicylic acid (DNS) method and the volatile acidity was determined following the method proposed by Miller, L [19 (link)].
The organic acids in wine samples were based on a previous method with some modifications [6 (link)]. Each sample was centrifuged and filtered through a 0.22 μm nylon membrane, and organic acids were identified by HPLC equipped with a Spursil C18 column (250 mm × 4.6 mm × 5 μm, Dima Technologies, Shanghai, China). The column oven temperature was maintained at 20 °C. The injected sample volume was 10 µL, while the mobile phase was 0.1% (v/v) formic acid at a flow rate of 1 mL/min.

The determination of soluble solids content and titratable acidity was based on juice squeezed from 10 peaches randomly selected from each cultivar. Soluble solids content was determined by sugar refractometer (Atago PR-101R, China) [23 (link)]. Titratable acidity was measured by using titrated NaOH (0.1 mol/L) and indicated using a percentage of malate (%) [24 (link)]. Three replicates were used in each group.

The SSC of the flat peaches was determined in accordance with the approach of Deena Ramful et al. (2011) via the utilization of a sugar refractometer (Atago PR-101R, Tokyo, Japan) after pressing and filtering the fruit residues [31 (link)]. Referring to Mohd Fadzelly Abu Bakar et al. (2009)’s method, with some improvements, the TA was determined by titration with NaOH (0.1 mol/L), and the expression of the results was the percentage (%) of malic acid [32 (link)]. Each replicate contained 10 fruits and all assays were carried out in triplicate.

Total soluble solids were analyzed by using a digital refractometer (Atago PR-101R, Tokyo, Japan). The titratable acidity was expressed as percent malic acid per 100 g, whose content was titrated to pH 8.1 with NaOH (0.1N). All analyses were performed in triplicate.

After homogenizing the collected fruit flesh samples, a digital refractometer was used to determine the total soluble solid content (Brix %) based on the refraction method described by NY/T 2637-2014 (Atago PR-101R, Tokyo, Japan). Based on GB/T 12456-2008, the titratable acidity (%) was determined by NaOH acid-base titration method. Based on the Agricultural Standard NY/T 2742-2015, the total sugar (%) was measured by the anthrone-sulfuric method. Based on GB 5009.86-2016, the vitamin C content (mg/100 g) was determined by molybdenum blue spectrophotometry. Based on GB/T 5009.5-2003, the protein content (g/100 g) was detected using the kjeldahl nitrogen method. Each replicate contained 20 fruits and all determinations were performed in triplicate.