INTRODUCTIONBrassicaceae family comprises a large numberof plant species distributed all over the world exceptAntarctica. This family includes approximately 338genera and 3700 species [1]. Fresh or preserved, cabbagehas been part of human diet since ancient times [2].Brassica oleracea L. and Brassica rapa L. are themost popular representatives of Brassica vegetables.They are almost completely edible, e.g. leaves,inflorescence, root, stem, and seed. Their excellentadaptability makes it possible to cultivate them indifferent seasons and environments. In the Occident,98Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105consumers prefer B. oleracea var. capitata, especiallywhite cabbage and red cabbage. Oriental cuisine featuresmostly B. rapa var. glabra Regel (Chinese cabbage)or B. rapa ssp. chinensis (L.) Hanelt (pak choi) [3].Brassica vegetables have low concentrations ofprotein and fat, which makes them popular low caloriefoods. In addition, they are rich in fiber, such mineralsas calcium and iron, and such bioactive compounds aspolyphenols and glucosinolates [4]. Calcium is essentialfor human diet. Dairy products are great sources ofcalcium, both qualitatively and quantitatively. However,people with lactose intolerance and vegans refrain fromdairy products, which makes Brassica vegetables anexcellent source of the recommended daily calciumintake. Indeed, cabbage has high concentrations ofcalcium, iron, selenium, copper, manganese, and zinc.Unfortunately, it also contains phytates that may formcomplexes with calcium, thus reducing its bioavailabilityand nutritional value [5].The past decade has seen an increase in scientificinterest to the antioxidant properties of dietary plantpolyphenols. These secondary metabolites can actas reducing agents (free radical terminators), metalchelators, singlet oxygen quenchers, and hydrogendonors [6]. Furthermore, epidemiological studiesstrongly suggest that long term consumption of plantpolyphenols prevents degenerative diseases associatedwith oxidative stress [7]. Some recent studies alsoshowed that cruciferous vegetables decrease the riskof several types of cancer, which makes cabbage afunctional food [2].Cabbage can be consumed raw as part ofsalads, condiments, or juice. It can be subjected tothermal processing, e.g. steaming, boiling, roasting,microwaving, etc., or fermentation (sauerkraut, kimchi,etc.) [2]. Recent studies demonstrated that Brassicavegetables lose their nutrient and health-promotingproperties if overheated during domestic cooking [4, 8].However, fermentation is known to enhance theirnutritional properties [9]. Fermentation is one of theoldest ways of food processing and preservation. It isa spontaneous process carried out by lactic bacteriapresent in vegetables tissues. Fermentation increasesthe safety, sensory properties, and shelf-life of foods. Italso promotes the release of bioactive compounds andreduces anti-nutritional factors [10].Food safety and shelf-life are associated withmicrobial competition and the synthesis of inhibitorymetabolites, such as lactic acid, acetic acid, hydrogenperoxide, diacetyl, ethanol, bacteriocins, and biosurfactants[10]. Lactic fermentation improves the nutritionalvalue of cabbage, as well as its antioxidant activities.Lactic fermentation reduces phytates, thus improvingthe bioavailability of essential dietary nutrients, suchas minerals, e.g. Ca2+, Zn2+, Mg2+, Mn2+, and Fe2+/3+,proteins, and amino acids [11].Different databases feature the same nutritionaldata on Brassica vegetables (energy, fat, protein,mineral content, and carbohydrates) [12]. However, thesituation is very different when it comes to the content ofbioactive compounds [2]. The profile and concentrationof phytochemicals depend on the cultivar, fertilization,agricultural conditions, environment, sowing season,and processing [13]. Furthermore, different studiesreport different effects of fermentation on the totalphenolic compound and antioxidant activity [4, 9, 10,14]. So far, no studies have featured the changes inthe total phenolics and antioxidant activity that occurbetween cabbage tissue and brine.The research objective was to evaluate the effectof spontaneous fermentation on: 1) phytase activity,calcium, and phytic acid concentrations; 2) total phenoliccontent and antioxidants activity of methanol extracts,water extracts, and brine throughout the fermentationof three Brassicaceae cabbages harvested in Patagonia(Argentina).STUDY OBJECTS AND METHODSPreparing the ferments. Chinese cabbage (Brassicarapa var. glabra Regel), white cabbage (Brassicaoleracea var. capitate f. alba), and red cabbage(B. oleracea var. capitata f. rubra) were obtained froma local farm of Valle Inferior del Río Chubut locatedin Patagonia, Argentina. The cabbages were plantedin March 2020 and harvested in June 2020. Before thefermentation, each cabbage head was stripped of dryouter leaves. The cleaned cabbage heads were choppedin a shredder into 2 mm thick strips and mixed with3.0 % (w/w) of salt. Sterile water homogenized themedium (5 mL/100 g of cabbage). Each cabbage wasspontaneously fermented at 18°C for 30 days. Thefermentation was performed in duplicate.Fermentation parameters. The total content oflactic bacteria and pH were monitored during thefermentation process on days 0, 1, 2, 3, 4, 5, 10, 15,20, 25, and 30. At the beginning of the process, theseparameters were examined after 6 and 12 h. The pH ofthe ferments was measured using a pH meter (modelOrion 410A). The lactic bacteria count was monitoredby incubating on MRS agar at 30°C for 48 h [15]. Theresults were expressed as colony forming units permilliliter of experimental sample (CFU/mL).Preparing the solvent extracts and brine. Duringfermentations, the solid and liquid samples werewithdrawn on days 0, 1, 3, 5, 10, 15, 20, 25, and 30. Toprepare the solvent extracts, solid samples were driedat 37°C until constant weight to avoid degradation ofthermal-sensitive compounds. After that, they wereground. Methanol and distilled water (1:10 m/V dilution)were used to prepare the extracts. For the methanolextract, the mixes were incubated for 3 h at 37°C understirring. For the water extract, they were autoclavedfor 15 min at 120°C. Both extracts were centrifuged at13,000×g for 15 min at 25°C. The supernatants werestored at –20°C, while the brine samples (liquidmaterial) were stored at –20°C.Measuring calcium. The o-cresolftaleín complexonecolorimetric method was used to determine the99Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105amount of calcium in the cabbage brines. Briefly,50 μL of sample were mixed with 950 μL of reactionmix composed by 3.7 mM of cresolphtalein complexoneand 0.2 mM of amino methyl propanol solution (pH 11).The calcium content in the brines was determinedagainst the calcium standard curve (0–55 μg Ca/mL).The absorbance was measured at 570 nm using a Jenwayspectrophotometer (UK). The results were expressed asmg calcium per 100 mL brine (mg Ca/100 mL).Phytic acid determination. The content of phyticacid was evaluated using an enzymatic method kit(Megazyme International, Ireland), based on itshydrolysis and further determination of free phosphorus.The procedure followed the manufacturer’s instructions.The phosphate released from phytic acid was measuredusing a modified colorimetric molybdenum blue assaydescribed by McKie et al. [11]. The color reagentwas prepared with a solution of 0.6 M sulfuric acid(32 mL/L), ammonium molybdate (5 g/L), and ascorbicacid (20 g/L). After enzymatic treatment, 1.0 mL ofcolor reagent was added to 50 μL of supernatant. Thesystem was incubated for 30 min at 50°C, and theabsorbance was measured at 820 nm. A standard curvewas constructed with dipotassium phosphate (K2HPO4)(0–0.4 μg/mL). The results were expressed as mgK2HPO4/100 mL brine. The concentration of phytic acidwas calculated on the basis of free phosphorus using theformula suggested by McKie et al. [11].Phytase activity of the brine. Phytase activitywas determined by measuring the amount of inorganicphosphate released from sodium phytate as proposedby De Angelisa et al. [16]. Briefly, 180 μL of reactivecontained 5 mM of sodium phytate and 200 mM ofsodium acetate buffer (pH 5.0). This amount was addedto 20 μL of brine. After 15 min of incubation at 37°C,the reaction was stopped by adding an equal volumeof 15% trichloroacetic acid. Afterward, the phosphatereleased was determined by the previously describedammonium molybdate method. One unit of phytaseactivity was defined as 1 μmol of phosphate producedper min per mL of brine under the assay conditions. Theresults were expressed as milli-units (mU).Measuring the total phenolics. The total phenoliccontent was determined using the Folin-Ciocalteaureagent according to previously published procedures,with minor modifications [17]. An aliquot of 50 μL ofextract was mixed with 100 μL of Folin-Ciocalteu´sphenol reagent and kept for 10 min. Then, Na2CO3(1.0% m/V; 1.0 mL) was added and kept for 90 minat 25°C. The absorbance was measured at 750 nm.A calibration curve was based on gallic acid asstandard. The results were expressed as milligramgallic acid equivalents per 100 g of dry weight(mg GAE/100 g DW).Determination the antioxidant activity. Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay.The free radical scavenging activity of the sampleswas evaluated by 1, 1-diphenyl-2-picryl-hydrazyl(DPPH) method as described by Chen et al., with somemodifications [18]. Briefly, 900 μL of an ethanolic DPPHsolution (100 μM) was added to 100 μL of sample atvarious concentrations. After 30 min of incubationin the dark at 25°C, the absorbance was measured at517 nm using a spectrophotometer. A standard curvewas constructed with Trolox as a reducing agent(15–250 μg/mL). The results were expressed asmilligram Trolox equivalents per 100 g of dry weight(mg TE/100 g DW).Cupric reducing antioxidant capacity (CUPRAC)assay. Cupric reducing antioxidant power (CUPRAC)was used to determine the antioxidant capacity ofthe sample as described by Gouda et al., with minormodifications [19]. An aliquot of 100 μL of sample wasmixed with 900 μL of reaction mix. The reaction mixconsisted of 2 mL of Neocuproine solution (5 mM),1 mL of Cl2Cu (0.01 M), and 3 mL of acetate buffer(50 mM, pH 5.0). After shaking and incubating for1 h in the dark, the mix was tested for absorbance at450 nm. A calibration curve was prepared using Troloxas standard (15–250 μg/mL). The results were expressedas mg of Trolox equivalent per 100 g of dry weight(mg TE/100 g DW).Total antioxidant capacity. The total antioxidantcapacity of the ferments was calculated by adding partialantioxidant activity of extracts and liquid phase (brine)contained in 100 g of edible material to simulate theantioxidant activity per sample. The same procedure wasrepeated for each vegetable and antioxidant parameter,i.e. DPPH, CUPRAC, and total phenolics. The resultswere expressed as milligram Trolox equivalents per100 g of fresh weight ferment (mg TE/100 g FW).Statistical analysis. All assays were carried out induplicate, unless mentioned otherwise. The data wereanalyzed by ANOVA, and the means were comparedby the minimum significant difference test at P < 0.05,using the Statgraphics Centurion XVI software.RESULTS AND DISCUSSIONFermentation parameters. Lactic bacteria andpH helped monitor the evolution of the fermentationprocess. Spontaneous fermentation of cabbage relieson autochthonous lactic bacteria present on the rawsubstrate. Organic acids decrease pH and increase thetitratable acidity of the raw material.The pH of raw white cabbage, red cabbage, andChinese cabbage were 6.0, 5.9, and 6.1, respectively(Fig. 1). The samples of red and Chinese cabbagedemonstrated a similar decrease in pH. In both cultivars,the lowest values were observed on day 4 and remainedstable over 30 days (Figs. 1b and 1c). The white cabbageshowed no sharp decrease of pH during fermentation.The lowest value was achieved on day 10 and remainedstable (Figs. 1a vs 1b and 1c).The initial population of lactic bacteria was2.1, 2.1, and 2.5 log CFU/mL in the white, red,and Chinese cabbages, respectively (Fig. 1). Thistrend confirms previous reports by R. Di Cagnoet al. and J. Beganović et al. [10, 20]. While the100Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105highest count was observed on day 5 (9.9 logCFU/mL), the red cabbage sample approachedits maximal counts on day 3 (9.4 log CFU/mL)(Fig. 1b). A similar curve was observed for the Chinesecabbage fermentation; however, the maximal countswere detected after day 4 (9.7 log CFU/mL) (Fig. 1c).Regarding the white cabbage, lactic bacteria populationincreased slower than in other samples and reachedits maximum (9.2 log CFU/mL) on day 5 (Fig. 1a). Inall the cases, once the peak was reached, the bacteriapopulations began to decrease. On day 30, the lacticbacteria cell counts were 5.0, 5.9, and 5.7 log CFU/mLfor red cabbage, white cabbage, and Chinese cabbage,respectively (Fig. 1).Calcium, phytic acid, and phytase activity.Figure 2 shows the changes in the phytase activity andcalcium and phytic acid concentrations that occurred inthe brine during fermentation. The raw samples of redand Chinese cabbage (Figs. 2b and 2c, respectively)contained comparable amounts of water-soluble calcium,whereas the white cabbage appeared to have a muchlower concentration (Fig. 2a).The initial level of phytic acid was almost the samefor all three cultivars. The raw sample of Chinesecabbage showed the highest phytase activity (Fig. 2c).The initial specific activities of white and red cabbageswere 39.54 ± 18.67 (Fig. 2a) and 56.71 ± 8.20 mU(Fig. 2b), respectively. The enzymatic activity wassupplied exclusively by vegetal tissue during earlyFigure 1 pH and total lactic acid bacteria counts grownon MRS agar in sauerkraut brine during spontaneousfermentation for white cabbage (а), red cabbage (b),and Chinese cabbage (c). Each value is mean ± SD of twomeasurementslog CFU/mL(а)(b)(c)log CFU/mL log CFU/mLlog CFU/mLFigure 2 Calcium, phytic acid, and phytase activity duringfermentation for white cabbage (а), red cabbage (b),and Chinese cabbage (c). Each value is mean ± SD of twomeasurementsmg/100 mL mg/100 mL mg/100 mL(а)(b)(c)101Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105fermentation, and then bacterial phytase brought aboutphytate hydrolysis [21].The highest phytase activity was detected betweendays 5 and 10 in the samples of white and red cabbage,when the population of lactic bacteria reached itsmaximum (Figs. 2a and 2b). After that, the valuesremained constant. In the sample of Chinese cabbage,the maximal activity was detected on day 10 (Fig. 2c),which coincided with the maximal viable cell count oflactic bacteria.As the fermentation process advanced, thephytate concentration decreased and the amount ofsoluble calcium increased in all the samples. Thisphenomenon was more pronounced in Chinese cabbagewhen the phytase activity had its highest value. Thelowest phytate concentration and the highest calciumconcentration were achieved on day 30. The assays forall the samples proved that the highest phytase activityoccurred under acidic conditions.Phytic acid (myo-inositol-6-phosphate) is the majorstorage form of phosphorous and represents 50–85%of total phosphorous in plants [21]. This compoundand its derivatives are the main inhibitors of divalentmineral absorption in the gastrointestinal tract due to theformation of insoluble and indigestible complexes [22].Hence, it may decrease the calcium bioavailabilityin cabbage [21]. However, this point of view is nowcontroversial since several studies demonstrated thatthe myo-inositol-6-phosphate consumption may beassociated with some health benefits. The antinutrienteffect of phytic acid has not been fully demonstratedin vivo. On the other hand, phytic acid exerts antiinflammatoryand anticancer activities and diminishesthe risk of osteoporosis [23].Phenolic compounds. Phenolic composition andantioxidant activity depend mainly on the type ofextraction solvent. The choice of solvent depends mainlyon the chemical nature and polarity of the compoundsto be extracted. Methanol and water are widely usedas solvents in vegetable and plant tissues [14]. In thisstudy, methanol and water helped measure phenoliccompounds and antioxidant activity in the cabbagesamples during fermentation.Figure 3 shows the total phenolic content in theextracts (methanol and water) and brines of white, red,and Chinese cabbages. Regarding the white cabbagesample, the water and methanol extracts exhibiteda similar total phenolic content. However, the totalphenolic content in the water extracts of red and Chinesecabbages was much higher than in the methanolicextract (Figs. 3b and 3c). Probably, the solubility ofphenolic compounds depended on extraction conditions,e.g. the chemical structure of solvents, dielectricconstant, time, temperature, phytochemical properties,etc. However, thermal treatment is known to damagesome phenolics [24].The total phenolic content in the extracts and brineof red cabbage was higher than in the samples of whiteand Chinese cabbage. This trend was in agreement withprevious studies. For instance, Tabart et al. [25] reported1851 mg GAE/100 g DW in red cabbage; Vicas et al.[26] – 980–1220 mg GAE/100 g DW in white cabbage;Seong et al. [27] – 347.46 ± 32.17 mg GAE/100 g DW inChinese cabbage. In vegetables, phenolics exist mostlyin conjugated forms through hydroxyl groups with sugaras glycosides. Lactic bacteria possess an enzymaticbattery that can convert phenolics to aglycone forms,which are simpler and biologically more active [28].Furthermore, during fermentation, pectic enzymesmay soften cabbage texture, thus releasing phenolicscompounds from the solid to the liquid phase [27].Lactic fermentation promoted a significantdecreased in the total phenolic content in the redand white cabbage extracts (methanol and water)after 3–5 days of incubation (Figs. 3a and 3b).Figure 3 Total phenolic content in methanol extract (ME),water extract (WE), and brine during fermentation for whitecabbage (а), red cabbage (b), and Chinese cabbage (c). Eachvalue is mean ± SD of two measurements(а)(b)(c)mg GAE/100 mL mg GAE/100 mL mg GAE/100 mL102Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105Afterward, the total phenolic content droppedslowly and remained almost constant until the endof lactic fermentation. The total phenolic contentin the methanol and water extracts decreasedalmost by half. On the contrary, the brine samplesdemonstrated a significant increase between days 3and 5, and then the concentration remained almoststable until the end of storage. The Chinese cabbagesample showed a slight decrease in the total phenoliccontent in methanol and water extracts throughout thefermentation (Fig. 3c).Antioxidant activity. The antioxidant activitywas evaluated by DPPH radical scavenging assay andCUPRAC reduction assay. Both are electron transferbasedmethods, frequently used to determine theantioxidant activities of phenolic compounds [6].Figure 4 illustrates the antiradical activity of methanoland water extracts against DPPH radical. The methanolextract contained significantly less reduction power thanthe water extract in all the cabbage samples. Probably,this solvent failed to provide efficient extractionof compounds with antioxidant activity. The rawFigure 4 Antioxidant activity (DPPH assay) in methanolextract (ME), water extract (WE), and brine duringfermentation for white cabbage (а), red cabbage (b),and Chinese cabbage (c). Each value is mean ± SD of twomeasurementsFigure 5 Antioxidant activity (CUPRAC assay) inmethanol extract (ME), water extract (WE), and brineduring fermentation for white cabbage (а), red cabbage (b),and Chinese cabbage (c). Each value is mean ± SD of twomeasurementsmg TE/100 mL mg TE/100 mL mg TE/100 mL(а)(b)(c)mg TE/100 mL mg TE/100 mL mg TE/100 mL(а)(b)(c)103Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105sample of red cabbage showed the highest antioxidantcapacity with 1050.44 ± 71.33 TE/100 g DW and616.63 ± 49.80 mg TE/100 g DW in water and methanolextracts, respectively (Fig. 4b). Afterwards, these valuesdeclined until the end of fermentation.On the contrary, in the brine, the values kept risinguntil day 5 and then remained stable. The extracts ofwhite and Chinese cabbages displayed a significantlylower DPPH radical scavenging activity than the extractsof red cabbage (Figs. 4a and 4c). These trends confirmedprevious reports [29]. The methanol and water extractsof white cabbage exhibited a slight decrease in theantiradical activity, while its brine demonstrated anincrease during the first 5 days of fermentation (Fig. 4a).However, no significant differences in the antioxidantactivities were observed in the Chinese cabbage extracts.A significant increase was detected in the brine duringthe first 10 days of fermentation, but it remainedconstant until the end of fermentation (Fig. 4c).Table 1 Contribution of water extract and brine to the totalphenolic content of each individually fermented cabbageTotal phenolic content, mgGAE/100 mLTime,daysWhite cabbage Red cabbage Chinese cabbage0 36.27 ± 2.26 24.35 ± 10.82 51.88 ± 2.011 35.57 ± 2.13 32.17 ± 9.00 68.31 ± 4.093 40.41 ± 3.18 92.95 ± 10.05 69.78 ± 4.775 42.24 ± 2.34 161.45 ± 9.83 70.30 ± 5.4610 40.48 ± 2.21 161.23 ± 15.23 71.81 ± 7.8115 33.67 ± 1.99 159.73 ± 11.67 70.85 ± 6.2420 33.74 ± 1.72 168.33 ± 12.43 71.48 ± 1.9625 35.09 ± 3.25 173.17 ± 7.98 73.77 ± 2.1530 36.21 ± 1.85 184.75 ± 11.90 76.51 ± 1.75*Each value is mean ± standard deviation of three measurementsThe values were expressed in mg of Gallic Acid Equivalents(GAE)/100 g of fresh weightIn all the cases, the values of antioxidant capacityobtained with CUPRAC assay (Fig. 5) were higher thanthose obtained with DPPH method. This trend could beexplained by the ability of CUPRAC method to measurehydrophilic and lipophilic antioxidants simultaneously,while DPPH detects only those molecules that aresoluble in organic solvents, particularly in alcohols [30].The antioxidant capacity of the red and whitecabbages decreased significantly in the methanol andwater extracts during day 1 and increased significantlyin the brine (Figs. 5a and 5b). In the white cabbage,these changes occurred between days 5 and 10. For thered cabbage, the decrease was observed on day 5 in themethanol extract and on day 15 in the water extracts.The maximal value in brine was achieved after 5 days.Regarding the Chinese cabbage samples, acomparable trend could be observed between thevalues obtained with DPPH radical scavenging assayand CUPRAC method. The concentration of reducingagents in dry matter decreased slowly in the waterextract, while the methanol extract showed no significantdifferences. A slight but significant increase in theconcentration was detected in the brine (Fig. 5c).The antioxidant capacity presented a sharp increaseon day 1 (Figs. 4 and 5). This trend was due to the highdriving force produced by concentration gradients of thesubstance that tends to equilibrate the medium. In thisprocess, water flows from the solid phase to the liquidphase and brings some solutes from the vegetables. Thisphenomenon is due to transfer rates that increase ordecrease until equilibrium is reached [31].Overall evaluation of total phenolics andantioxidant activity. The total phenolic content andantioxidant activity in the white and red cabbagesamples decreased in the dry matter and increased in theliquid phase. This phenomenon was less pronounced inthe Chinese cabbage sample. However, these data alonecannot estimate the total variation of the antioxidantcapacity throughout the process: both phases contributedto the phenolic content and scavenging activity since thecabbages were not to be consumed dry.Table 2 Contribution of water extract and brine to the total antioxidant capacity (DPPH and CUPRAC) of each individuallyfermented cabbageDPPH assay, mgTE/100 mL CUPRAC assay, mgTE/100 mLTime, days White cabbage Red cabbage Chinese cabbage White cabbage Red cabbage Chinese cabbage0 13.04 ± 0.79 52.15 ± 4.85 6.44 ± 0.52 15.01 ± 1.04 104.94 ± 2.13 16.84 ± 0.361 14.10 ± 1.01 64.27 ± 2.32 8.86 ± 0.19 18.66 ± 0.80 122.38 ± 12.63 26.46 ± 0.623 11.94 ± 1.56 80.45 ± 6.05 8.28 ± 0.65 20.94 ± 0.12 166.01 ± 6.19 25.24 ± 1.035 11.37 ± 0.68 97.98 ± 6.88 8.44 ± 0.46 22.20 ± 0.93 213.06 ± 7.82 22.23 ± 2.0110 11.04 ± 1.17 89.93 ± 6.61 9.28 ± 0.16 19.60 ± 1.80 231.88 ± 15.18 23.92 ± 1.2115 9.64 ± 0.55 81.44 ± 0.41 10.24 ± 1.17 16.70 ± 1.70 193.52 ± 20.26 24.59 ± 2.9220 9.79 ± 1.11 81.32 ± 5.57 10.21 ± 0.91 17.99 ± 0.28 194.01 ± 15.47 24.30 ± 0.0125 10.07 ± 0.43 78.42 ± 5.80 10.29 ± 0.01 16.26 ± 0.05 187.33 ± 13.73 23.69 ± 2.6230 8.68 ± 0.91 66.81 ± 0.85 9.98 ± 0.00 15.08 ± 1.87 176.77 ± 4.79 24.48 ± 3.11* Each value is mean ± SD of three measurementsThe values were expressed in mg of Trolox Equivalents (TE)/100 g of fresh weight104Parada R.B. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 97–105Tables 1 and 2 show the results obtained by addingthe values of dry matter and brine. These results canbe considered the total polyphenol content and thetotal antioxidant activity of the fermented cabbages.Regarding the samples of red and Chinese cabbages, thetotal phenolic content and the total scavenging activityin the water extracts and brine gradually increased andreached plateau after about 5–10 days, which coincidedwith the highest population of lactic bacteria. In thewhite cabbage samples, the total phenolic contentand the total antioxidant capacity in the water extractand liquid phase exhibited slight changes. By the endof fermentation, the total phenolic content and theantioxidant activity were similar or smaller, in the caseof radical scavenging activity measured by DPPH.To sum up, the fermentation increased the totalphenolic content and the antioxidant activity in theliquid phases of red and Chinese cabbages. The redcabbage sample had the highest total phenolic content.CONCLUSIONFermentation was able to significantly improve thequality and functionality of Brassica L. cabbages. Thetest samples showed a significant increase in phytaseactivity, which promoted the decrease of phytic acidand the increase of free calcium. Fermentation raisedthe total phenolic content and the antioxidant activitybecause of the individual contribution of the solid andliquid phases to total scavenging capacity.CONTRIBUTIONRomina Parada is responsible for conceptualization,methodology, software, validation, formal analysis,investigation, reviewing, proofreading, and visualization.Emilio Marguet is responsible for conceptualization,methodology, formal analysis, investigation,and drafting. Carmen Campos is responsible forconceptualization, software, formal analysis, writingreviewing,and editing. Marisol Vallejo participated inconceptualization, methodology, writing, reviewing,editing, and visualization.CONFLICT OF INTERESTThe authors declare that there is no conflict ofinterests regarding the publication of this article.