Cauliflower was procured from local market and was brought to the Food processing pilot plant of the department of Food science and Technology. The vegetables which were free from physical damage, dirt, dust and other defects were used for the product formulation.

The chemicals and reagents used for Physico-chemical and microbial were purchased from Sigma-Aldrich Chemie (Buchs, Switzerland), Himedia India. All the chemicals were of analytical grade.

The vegetables were thoroughly washed under tap water. Surface leaves of cauliflower were removed and florets were separated from the central stalk. The cauliflowers were peeled and tops were cut off. Washed cauliflowers were shredded into pieces (3-4 cm in length and 1 cm thick) and were weighed. The spices like ginger and garlic were peeled, chopped and then coarsely pounded. Mustard, red chilli and turmeric were used in powder form.

er, carom seeds were used in intact form. Shredded vegetables were dried under sunlight for 3 hours in order to remove the surface moisture with periodic turnings. The dried vegetables were mixed with specific quantity of spices and other ingredients (Table 1). 3% salt was added to the mixture on w/w basis. The product so obtained was then filled in previously sterilized plastic containers. The filled containers were stored in the incubator (Memmert INE 500, Germany) at 21⁰C. The containers were monitored continuously until desirable acidity was achieved. The fermented products were divided into two portions. One portion of them was subjected to sodium benzoate treatment at concentrations of 350, 450 and 550 ppm while as the other was subjected to microwave treatment for 2.5, 3.5 and 4.5 min. The treated products were then filled into glass bottles separately and was labeled as S₁ (350 ppm), S₂ (450 ppm) S₃ (550 ppm) M₁ (2.5 min), M₂ (3.5 min) and M₃ (4.5 min), respectively. One bottle kept untreated was used as control (C).

The pH measurements of samples were carried out at regular intervals of time. Samples were homogenized (wise TIS homogenizer HG-15A, Korea) and left undisturbed for 20 minutes. The samples were centrifuged at 1200 rpm for 20 minutes. The supernatant obtained was used for the analysis of pH. The pH of the samples was determined by pH meter (HANNA-HI 2215 pH/ORP meter, Romania).

Titratable acidity of the samples was determined by titrimetric method. Sample of 10 gm was homogenized (Wise TIS homogenizer HG-15A, Korea) with 100 ml of distilled water. To the 10 ml of aliquot, few drops (2-3) of phenolphthalein was added as an indicator. The acids (lactic acid) in the samples were titrated against 0.1N NaOH and expressed as mg lactic acid 100 gm of fermented pickle extracts. The percentage of the lactic acid was calculated as follows:  Acidity % =N× Eq. Wt . of acid × Vol. made Wt . of sample × Vol. of aliquot ×1000×100

Total plate count of each sample was done aseptically by transferring 1 mL of sample into 9 mL of sterile Peptone water buffered (Biolab, Merck, Germany). The contents were mixed thoroughly. MRS agar was used as nutrient media for the enumeration. Serial dilutions for each of the sample were done according to. All the glassware used during the microbial analysis was pre-sterilized. Plates were incubated at 37⁰C for 48 hours. The microbial load was expressed as log₁₀ cfu/g for each sample.

The color values of the fermented pickle samples during the storage period were determined using a Hunter Color Lab (Mini Scan XE Plus, model No. 45/0L, Hunter Associates Laboratory, Reston,VA). The instrument was calibrated with black and white tiles before color measurement. The “L*” value indicates the lightness, with 0–100 representing dark to light. The “a*” value gives the degree of the red–green color, with a higher positive “a” value indicating more red. The “b*” value indicates the degree of the yellow–blue colour, with a higher positive “b” value indicating more yellow. The average value of three replicates was calculated.

The textural analysis of the each sample was done by 5-blade Kramer share cell (HDP/KS5) using texture analyzer (Stable micro system, Model TA.XT plus, England). Texture profile analysis (TPA) was performed in duplicate on each sample at room temperature. Samples were taken from the center of each glass bottle. The conditions for texture analysis were as follows: test speed 3.00 mm/sec, post- test speed 10.00 mm/sec, maximum load 50 kg, distance 25 mm and trigger type ‘button’. Prior to analysis, the height of the blades was calibrated. The texture profile analysis was obtained by graphing a curve using force (g) and time (sec) plots. A value of mean maximum force (firmness) was determined for each sample.

The sensory analysis of the fermented product was done on the basis of 9- point hedonic scale for attributes like, flavour, sourness, firmness and color. Sensory analyses were carried out by the research scholars and faculty members (25 to 48 years of age) in the Department of Food Science and Technology. Samples were coded and served at room temperature with water. Samples were given to panelists separately for unbiased evaluation of sensory attributes. Taste was evaluated as sourness, texture as firmness, flavour intensity. However, overall acceptability was evaluated as the sum of all the sensory attributes considered and was calculated.

The statistical analyses were performed using the IBM SPSS statistics 21. The differences among the treatments were evaluated statistically by one-way analysis of variance (ANOVA) and Duncan’s multiple tests. All data were two sided at the 5% significance level and are reported as means ± standard deviations (SDs).

The values of the microbial count for the different samples are given in the Fig. 1.

The microbial count in the control (C) was found to increase rapidly reaching to a value of 8.2 log₁₀ cfu/g at the 15-day of fermentation and continued to increase to 8.7 log₁₀ cfu/g at 30-day of fermentation. Microbial count increased non-significantly in S₁ (8.0- 8.5 log₁₀ cfu/g), S₂ (8.1-7.7 log₁₀ cfu/g) and S₃ (8.3-6.9 log₁₀ cfu/g) as compared to control indicating that sodium benzoate up to concentration of 550 ppm does not show any inhibitory effect on LABs. These results are in accordance with the previous studies (Turantas et al. 1999). But in case of M₁, M₂ and M₃ there was a significant decrease in microbial count throughout storage study. The observations revealed that microwave treatment had a better control on microbial population as compared to sodium benzoate. These results are in agreement with the earlier study (Arenzana et al. 2012).

The overall acceptability of the samples are presented in the table 2. The score for S₁, S₂ and S₃ were 8.3, 8.1 and 8.6, respectively which decreased to 7.1, 6.9 and 6.4 respectively after 30 days of storage. The score of M₁, M₂ and M₃ decreased from 8.5, 8.6 and 7.9 to 8.1, 6.8 and 7.5, respectively on the 30 day of storage. These results show that the overall acceptability of the M₁ received highest rating from the panelists. The sensory quality of the samples that were treated with sodium benzoate did not differ significantly from that of control. However the sample M₂ received significantly lower scores from the panelists among the microwave treated samples. The samples M₂ and M₃ received the lower scores due to the textural degradation by microwave heating. These results are in agreement with the earlier study (Turantas et al. 1999).

The results obtained for pH value are given in the Fig. 2. The pH value of the raw sample was 6.5 and was found to apparently decrease in different samples during storage. Several other authors have also reported such a decreasing trend in the pH values of the pickles during storage (Khaskheli et al. 2015; Turantas et al. 1999; Spiros et al. 2020; Dhanapal et al. 1994). In case of control (C) the pH value decreased from 5.74 to 3.70 on 30-day of fermentation. The same trend in the decrease of pH value in the garlic pickle has been earlier reported (Raja and Mir 2016). Sample M₁ showed decrease in the pH value from 5.62 at 15-day to 4.84 at the 30-day of fermentation. However the samples S₁, S₂ and S₃ did not showed any significant difference to that of control (C).

The values of the titratable acidity obtained for the different samples are given in the table 3. The value of acidity (as % lactic acid) for the raw material was 0.27. The values of acidity for S₁, S₂ and S₃ were 0.90, 0.91 and 0.93, respectively on the 15-day of fermentation which increased to 1.45, 1.43 and 1.48 %, respectively at 30-day of storage, thus suggesting a significant increase in acidity. The samples M₁, M₂ and M₃ showed an decrease in the acidity values from 0.97, 0.99 and 0.92 on the 15-day of fermentation to 0.96, 0.97 and 0.86 respectively at 30-day of fermentation. Increase in acidity of M₁, M₂ and M₃ samples during storage might be due to release of H⁺ and NH₃+ from putrifecation. It is thus evident from the results that microwave treatment had a better control on acid production than sodium benzoate and the effect can be attributed to destruction of lactic acid bacteria by microwaves (Arenzana et al. 2012).

The firmness (N) values obtained for control and samples treated with microwave and sodium benzoate are given in the table 4. All samples showed decrease in the firmness during storage. Sample S₂ showed the highest decline (4.9) at 30-day of fermentation. For the sample S₁, S₂ and S₃ the firmness decreased from 6.8, 6.9 and 6.9 to 5.3, 4.9 and 5.1, respectively after 30 days of storage. Samples M₁ (6.6) and M₂ (6.3) also show a decrease in the firmness after 30 days of storage. Similar trend were observed in pickled vegetables due to thermal processing (Fleming et al. 1993; Papageorge et al. 2003).

The values obtained for the instrumental color of the samples during storage study are given in the table (5). The “L” value showed a constant decrease in the control sample (38.97 to 36.38) during the storage. However “L” value increased in the S₁ (39.32 to 41.22), S₂ (39.86 to 43.11) and S₃ (42.41 to 43.26) samples. The “a” value increased continuously among all treated samples including control sample from day 0 up to day 30 of the fermentation. The “b” value showed increasing trend in all samples including control. Similar trend in instrumental color was observed in carambola pickle (Igrid and Neela, 2004).