Agriculture Reference
In-Depth Information
2.1.3. Measurements
When tomato was ripened, two fruits were harvested from one plant, and about 10 g tomato
flesh per fruit was taken along the longitudinal axis (24 fruits per treatment in total) then
homogenized for the following measurements. Different forms of Ca in the tomato fruits were
extracted and determined by adopting Ohat Y's method (Ohat Y, 1970), including Ca nitrate
and Ca chloride, water soluble organic Ca, Ca pectate, Ca phosphate and Ca carbonate, Ca
oxalate, Ca silicate, hereafter the above Ca forms were recording successively as Alc-Ca, H
2
O-
Ca, NaCl-Ca, HAC-Ca, HCl-Ca, Res-Ca based on the extraction solvent type. Other quality
indexes were evaluated by common testing methods (AOAC, 1990; Wang et al., 2011; Yang et
al., 2012): Vitamin C content was measured by the 2, 6-dichloroindophenol titrimetric method;
soluble sugar was measured by the anthrone method; soluble protein was measured by the
Coomassie brilliant blue method; nitrate content was measured by the ultraviolet spectropho‐
tometry method. For each treatment, thirty tomato fruits with a red or orange color were
collected randomly to determine the basic morphological parameters, containing long
diameter (L-diameter) and short diameter (S-diameter). Fruit weight was calculated from the
total number and weight of fruits harvested.
2.2. Results
2.2.1. Calcium solubility in LAB experiment preparation of EM-Calcium mixtures
According to the survey results from the measured Ca
2+
concentration, the Ca solubility was
calculated and showed in Table 2. Results indicated that the measured Ca
2+
concentration of
T5 and T4 was significantly higher (P<0.05) than that of T1, T2, T3. The Ca solubility of T4
reached the peak value of 89.5%, which was 22.17%, 31.00%, 9.90%, 9.79% higher than that of
T1, T2, T3, and T5 respectively. Therefore T4 was selected as the optimum formula applying
to the following field experiment on account of high calcium solubility. The eventually diluted
T4 solution used for the field experiment was acid, with the pH value of 4.7.
Treatment
Theoretical Ca
2+
concentration Measured Ca
2+
concentration
Solubility
T1
3.0‰
2.02‰d
67.33%
T2
4.0‰
2.34‰c
58.50%
T3
5.0‰
3.98‰b
79.60%
T4
6.0‰
5.37‰ab
89.50%
T5
7.0‰
5.58‰a
79.71%
Means within a column followed by the same letter are not significant at P<0.05 (Duncan's multiple range test).
Table 2.
Theoretical and measured Ca
2+
concentration after 6 days fermentation
