Sensory properties of green table olives prepared by different fermentation processes

ABSTRACT This study evaluated the effect of debittering fermentation methods on the sensory properties of green table olives. The panelist results of appearance, aroma, taste, and texture showed that the most preference sensory attributes are found in treated with NaOH followed significantly by the whole, scratchy and ticked. The panelist results varied and showed the higher values of overall appearance found in NaOH followed by the whole, scratchy, and ticked. Also, the higher values of overall flavor and taste found in treated with NaOH followed by ticked, scratchy, and whole. The higher values of overall texture found in whole followed by treated with NaOH, scratchy and ticked. The higher values of overall bitter taste found in whole followed by scratchy, ticked and treated with NaOH. In conclusion, despite of NaOH processing fermentation debittering method has the most sensory parameters but in general not big differences were found comparison with other methods.


Introduction
The olive trees (Olea europaea L.) are a main crop that grows in the Mediterranean regions (Al-Ismail, Ahmad, Al-Dabbas, Ajo, & Rababah, 2011). Olives are the most important fruit that supplies olive oil and table olives (Boskou & Visioli, 2003). Therefore, table olives from an economical point of view are considered one of the significant goods that provide oil with high nutritional value and possible therapy treatments (Ribarova, Zanev, Shishkov, & Rizov, 2003). Worldwide production of table olives according to the International Olive Council (IOC, 2017) is around approximately 3,020, 500 tons. Jordan is considered one of the most important countries in olive trees cultivation (12 million trees), it contributes about 72% of the total planted area, which is 36% of Jordanian lands. Jordan also has a considerable production of table olives, with around 20,000 tons in the 2016/2017 (Market Newsletter, 2008). Therefore, table olives are the main component of the Mediterranean diet as they contributed to the prevention of some chronic diseases such as cardiovascular disease (Charoenprasert & Mitchell, 2012). Moreover, olives from an economical point of view are considered one of the significant goods that provide oil with high nutritional value and possible therapy treatments (Ribarova et al., 2003). The fermentation process on table olives is carried out by Lactic acid bacteria (Romeo, Piscopo, Mincione, & Poiana, 2012). Lactic acid bacteria in which; gram-positive, gram-negative and yeast are the predominant microorganism that it's found on fermentable table olives (Fernández, Adams, & Fernández-Díez, 1997). However, hygienic practices on the fermentation process also organize salt content, temperatures, and a low oxygen requirement is necessary for the success process (Romeo et al., 2012). The progress of lactic acid bacteria will acidify the brine solution by dropping the pH to less than 4.5 (Fernández et al., 1997). Table  olives treated by Spanish style have a beginning pH range above Greek-style preparation of olives that olives directly brining after preparation (Balatsouras, 1990;Panagou, Tassou, & Katsaboxakis, 2003).
The marketing success of food products depend on many factors including consumer sensory satisfaction; were the determination of consumer expectations and attitudes for a given food, and expression of consumer demands into scientifically sound sensory descriptors are essential in the aiming of food marketing, besides other techniques, quantitative descriptive analysis (QDA) is a widely used sensory technique of product description by trained panels, It gives an opportunity to describe and compare food samples, as well as to match consumer demands (Yilmaz & Aydeniz, 2012). In order to assess consumer behavior, affective sensory testing procedures are used, where the primary purpose of affective tests is to assess personal responses posed by current and potential customers of products (Meilgaard, Civille, & Carr, 1991). Also, they demonstrated that acceptance and preference tests are carried out through several techniques. Yilmaz and Aydeniz (2012) investigated the ninepoint Hedonic scale which is a common technique used for consumer tests that aim to select the best suitable varieties for green table olive preparation based on sensory descriptors and consumer demands for successful marketing.

Sample collection
Four different varieties of green table olives; Nabali, Baladi, Crosodi, and k18 (their abbreviations in this study were included N, B, C, and K18, respectively), were collected from Irbid farms in October 2015.

Debittering methods
Olives were hand-picked when they developed a greenyellow surface color and normal large-size. The collected olives were subjected to sorting concerning their size and washed with tap water to be ready for the fermentation process. Four fermentation treatments were applied; whole, ticked scratches and treated with NaOH (their abbreviation H, D, T, and M, respectively). The de-bittering methods of table olive treated with NaOH were conducted as described by Ünal and Nergiz (2003) like the following, a 2% NaOH solution was added into the four glasses jars containers and the olives (7.5 kg from each variety of table olive) were kept for 8 hours in that solution. During this de-bittering process, penetration of sodium hydroxide solution into the olive flesh was detected by cutting the fruit halfway down its length to see how far the solution has penetrated the flesh from time to time. After penetration of NaOH in a depth corresponding to 2/3 of flesh thickness, the solution was poured with the aid of tap container and the fruits were subjected to water washing several times; 3 times at least to eliminate the excess of alkali solution remaining on the fruits. To ensure all alkaline are removed from brine solution 2 drops of phenol naphthalene were added to the brine solution. At the end of this period, the water was removed. The olives then placed into glass jars bottles (500 grams capacity) and a 10% NaCl brine solution was added to cover the olives. For whole table olives and de-bittering process olive placed into glass jars container contain tap water and kept for 24 hours, water was changed every 8 hours, and the rest of the fermentation process was similar to treated with NaOH table olives. For the ticked table olives fermentation process, the olives were beaten by hand stone and the process of the de-bittering olive was done as mentioned for the whole table olives. Scratchy table olives processed by knife then completed similarly as mentioned before. Olives filled into glass jars bottles of the four verities stored at room temperature for evaluation during 0, 1, 2 and 3 months for physiochemical (pH, acidity, color, texture, and chemical composition) and phytochemicals (total phenol, antioxidant, flavonoids) properties. For sensory evaluation similar procedures as described before were conducted. The fermentation process was monitored by recording its pH to determine the end of the fermentation process. These samples were heat treatments by water bath (72°C for 15 sec) and kept in a refrigerator until use.
The de-bittering methods of table olive treated with NaOH were conducted as described by Ünal and Nergiz (2003) as the following, a 2% NaOH solution was added into the four glasses jars containers and the olives (7.5 kg from each variety of table olive) were kept for 8 hours in that solution. During this de-bittering process, penetration of sodium hydroxide solution into the olive flesh was detected by cutting the fruit halfway down its length to see how far the solution has penetrated the flesh from time to time. After penetration of NaOH in a depth corresponding to 2/3 of flesh thickness, the solution was poured with the aid of tap container and the fruits were subjected to water washing several times; 3 times at least to eliminate the excess of alkali solution remaining on the fruits. To ensure all alkaline are removed from brine solution 2 drops of phenol naphthalene were added to the brine solution. At the end of this period, the water was removed. The olives then placed into glass jars bottles (500 grams capacity) and a 10% NaCl brine solution was added to cover the olives. For whole table olives and de-bittering process olive placed into glass jars container contain tap water and kept for 24 hours, water was changed every 8 hours, and the rest of the fermentation process was similar to treated with NaOH table olives. For the ticked table olives fermentation process, the olives were beaten by hand stone and the process of the de-bittering olive was done as mentioned for the whole table olives. Scratchy table olives processed by knife then completed similarly as mentioned before. Olives filled into glass jars bottles of the four verities stored at room temperature for evaluation during 0, 1, 2 and 3 months for physiochemical (pH, acidity, color, texture, and chemical composition) and phytochemicals (total phenol, antioxidant, flavonoids) properties. For sensory evaluation similar procedures as described before were conducted. The fermentation process was monitored by recording its pH to determine the end of the fermentation process. These samples were heat treatments by water bath (72°C for 15 sec) and kept in a refrigerator until use.

Determination of pH
pH is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles/liter, of hydrogen ions (Bargrizan, Smernik, & Mosley, 2017). More precisely it is the negative of the logarithm to base 10 of the activity of the hydrogen ion (Bates & Vijh, 1973). Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic pure water is neutral, at pH 7, being neither an acid nor a base (Bargrizan et al., 2017). Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively (Lim, 2006). The pH of the brine solution for four different types of green table olives at RT (25°C) was determined using a pH meter (pH 510, EUTECH instruments, Malaysia). The pH meter was calibrated with pH buffers at 4 and 7. The glass electrode was placed directly into the brine solution in each olives container, and the resulting pH values were recorded. During the storage period of fermentation, pH measured from the beginning of fermentation until 90 days of storage. For sensory analysis attributes for table olive varieties, a pH measured from the beginning of fermentation until the end of fermentation for each de-bittering method of fermentation record (3.5) in each de-bittering method of fermentation.

Acidity determination
In chemistry, free acid generally refers to any acid that can lose proton(s) in an acid-base reaction; however, the term is used slightly differently in other fields and used to describe acids such as phosphoric acid, sulfuric acid which are involved in renal physiology; where used to explicitly exclude ammonium (NH4+) as a source of acid, and is part of the calculation for net acid excretion and gets its name from the use of NaOH in acid-base titration to estimate the quantity of free acid (Lim, 2006). The acidity (expressed as a percent of lactic acid) was determined by titration of 10 ml of brine solution with a 1% phenol naphthalene indicator and 0.1 M sodium hydroxide solution. Three replicates were used to calculate the mean value. During the storage period of fermentation, acidity was measured from the beginning of fermentation process until 90 days of storage. For sensory analysis attributes for table olive varieties, acidity measured from the beginning of fermentation until the end of fermentation for each de-bittering method of fermentation (0.3 g LA/100 ml) in each de-bittering method of fermentation.

Descriptive analysis
Eight-member descriptive panel (3 males, 5 females and their ages from 23-40 years), who consumed fermented table olives frequently and at least twice per week, were trained according to the Spectrum de-bittering methodology (Meilgaard et al., 1991). The training process included theoretical and practical sessions held twice a week and that followed the main recommendations of the IOC standard Regulation (International Olive Council IOC, 2011). The experienced panelists took two sensory classes and have been trained for table olive products sensory evaluation for more than 300 hours. The performance of the panel was evaluated by using a mixed model of three-way ANOVA with interaction. The Spectrum de-bittering method involves scoring perceived intensities with references to a determined scale using standard attribute names with their standards that define a scale of intensity. There was no major difference in sensory parameters in comparison with ticked and scratchy table olives fermentation de-bittering methods. Instrumental texture results were agreed with descriptive analysis and consumer results. The panelist results of appearance, aroma, taste, and texture showed that and regarding the de-bittering methods of fermentation the most preference sensory attributes are found in treated with NaOH followed significantly by the whole, scratchy and ticked, respectively. Each treatment from 16 table olives was evaluated for aromatics, basic taste, and feeling factors attributes. Four 3-hour orientation sessions were necessary for the panel to develop the test de-bittering methodology necessary to describe the characteristics of the sensory attributes of fermented table olive samples. All samples were coded with random 3-digit numbers. At each of the test sessions, a warm-up sample was used to ensure that the panel was well trained. Panelists underwent an orientation session using table olives during which the panelists were able to narrow down the list of references for each descriptor Tables 1 and 2. The panelists used the orientation session to improve their reproducibility and accuracy. Panelists underwent an orientation session using table olives during which the panelists were able to narrow down the list of references for each descriptor Tables 1 and 2. The panelists used the orientation session to improve their reproducibility and accuracy. The appearance attributes were assessed by the whole panel on the complete sample before carrying out the tasting. Next, in each sample, first the odor was evaluated, then the flavor and, finally, the texture attributes. The evaluation of the odor was made by direct aspiration of the air over the tasting glass in 2 phases: first with the glass kept still to detect any possible defects, and then after shaking it gently to determine the different odor attributes. Four sessions of 1 hour (4 samples/session) were conducted to complete the analysis. The sixteen fermentation treatments were randomly in 3-digit numbers allotted and evaluated for the following attributes: 1) appearance: oval, glossy, greenness, and yellowness; 2) aroma: briny, ocean-like, musty, soapy, earthy, mushroom, vinegary and flora; 3) taste: sour, saltiness, hay, bitterness, oily, buttery and ripeness; and 4) texture: hardness, juicy moisture, crunchy and fibrous. A 15point intensity scale anchored by references as defined by the Spectrum de-bittering methodology was used in assigning values to the various descriptors.

Consumer testing
The consumer sample population was selected from among consumers in Jordan University of Science and Technology, who were 18-60 years of age and various socioeconomic backgrounds. Only those who consumed fermented table olives commonly were selected to participate in the study. With a target of 50 participants, a total of 75 were selected in anticipation of test no shows. Consumer testing was conducted at Jordan University of Science and Technology Laboratories (Irbid, Jordan). Consumers were directed to taste samples in individual tables and evaluate those using written instructions and ballots. Samples were coded with three random digit numbers and presented in a balanced order. Consumer testing was conducted at room temperature (Meilgaard et al., 1991). Each consumer was provided with sixteen plates individually and separately containing five fruits of each treatment of table olives. To eliminate carry-over factors, consumers were also provided with green apple at room temperature and water for mouth cleansing between samples. The consumers were asked to record their acceptability and intensity scores for overall appearance, overall texture, overall taste, overall flavor and overall bitter taste (9-point scale with 9 = like extremely and 1 = dislike extremely); overall bitter taste (9-point intensity scale with 9 = extremely bitter taste, and 1 = extremely not bitter taste).

Statistical analysis
Data in triplicate of physicochemical and sensory properties were analyzed using the general linear model (GLM) Odor of dried grass Dried grass wrapped in aluminum paper Artificial The scent of artificial fruit flavor (e.g. raspberry) Arti fruit/floral Fruity/Floral Natural Fruity/Floral The mild scent of natural fruit/flower (e.g. chrysanthemum) Extra virgin olive oil from Aloreña variety Vinegary The aroma of fermented vegetables and vinegar Vinegary Alcohol The aroma of ethanol Alcohol Fishy/Ocean-like The aromas of the ocean and of dried anchovy Fishy/ocean Cheesy The aroma of feta cheese Cheesy After: (Lee, Rudell, Davies, & Watkins, 2012;Rababah et al., 2005Rababah et al., , 2013Soldevilla et al., 2013) Siguiendo a: (Lee et al., 2012;Rababah et al., 2005Rababah et al., , 2013Soldevilla et al., 2013). Table 2. Description, definitions, references, and intensities used for sensory evaluation.

Sourness
The taste of citric acid Citric acid solution in spring water (0.05% and 0.08% citric acid) Bitterness The taste of caffeine 0.3 g of caffeine is dissolved in 1 liter of water 30 ml of dissolution in 50 ml plastic cup (0.05% and 0.08% caffeine) Saltiness The taste of sodium chloride 2 g of salt is dissolved in 1 liter of water. 30 ml of dissolution in 50 ml plastic cup (0.2% and 0.5% iodized salt) Flavor Ripeness The sensation of green and unripe vs. ripe olives Ripe Buttery The sensations related to high fat/oil content Butter Metallic The sensation related to canned vegetables Metal Pineapple juice (canned) Rancid The unpleasant flavor as a result of being stale Rancid Soapy/medicinal The sensation related to products containing soap Soap/medicn Gassy The sensation related to propane gas Gassy Texture/mouth feel Firmness Mechanical property of texture related to the strength required to attain a certain penetration of the olive.
Gordal olive with stone

Fibrousness
The texture of some raw vegetables (e.g. celery) A portion of celery Moisture release The amount of moisture released during chewing Moist (Cracker and Applesauce) Mouth coating The amount of mouth coating due to oil Mouth coat Chewiness The amount of time required to chew before swallowing Chewy Astringency Dry, puckering sensation on the tongue and palate Alum solution in spring water Residual The amount of particles left after swallowing Residual After: (Lee et al., 2012;Rababah et al., 2005Rababah et al., , 2013Soldevilla et al., 2013) Siguiendo a: (Lee et al., 2012;Rababah et al., 2005Rababah et al., , 2013Soldevilla et al., 2013).
procedure with JMP statistical package (JMP Institute Inc., Cary, NC, USA). Means were separated by LSD analysis at a least significant difference of P ≤ 0.05 values. Mean were separated by LSD (Least significant Difference) analysis at a least significant difference of 0.05 p-values.

Descriptive analysis
Descriptive sensory attributes scores are given in Table 3-4. As seen from the results there are some significant differences (P < .05) among all de-bittering methods of table olive varieties, for appearance: oval, glossy, greenness and yellowness, aroma: briny, ocean-like, musty, soapy, earthy, mushroom, vinegary and flora, taste: sour, saltiness, hay, bitterness, oily, buttery and ripeness and texture: hardness, juicy moisture, crunchy and fibrous. In general, and regarding the de-bittering methods of fermentation the most preference sensory attributes are found in treated with NaOH followed significantly by the whole, scratchy and ticked, respectively. Also, regarding the type of table olives, the highest panel preference was found in Baladi followed significantly by k18, Crosodi, and Nabali, respectively. The results of appearance in the de-bittering method of fermentation and the four types of table olives (Table 3) showed that there is no significant difference between de-bittering methods of fermentation, but the higher values of the oval were found in treated with NaOH followed by the whole, scratchy and ticked, respectively. The most glossiness was found in whole followed by scratchy, treated with NaOH and ticked, respectively, but there is no significant difference between the de-bittering method of fermentation. There is no significant difference between de-bittering methods of fermentation, but the higher values of greenness were found in ticked followed by the scratchy, whole and treated with NaOH, respectively. The higher values of yellowness were found in treated with NaOH followed by ticked, scratchy and whole, respectively, but there is no significant difference between de-bittering methods of fermentation. Our results are within and agreed with Yilmaz and Aydeniz (2012) who found that the oval appearance ranged from 1.5 to 10.7, **Means ± SD in the same column with the same letter are not significantly different (P ≤ 0.05). Todos los valores representan la media de tres repeticiones y se calculan en base húmeda. *Trt= método de desamargado de diferentes variedades, N= Nabali, C= Crosodi, B= Baladi, K= k 18 , H= aceituna de mesa entera, D= aceituna de mesa marcada, T= aceituna de mesa áspera, M= aceituna de mesa tratada con NaOH. **Las medias ± DE en la misma columna con la misma letra no son significativamente diferentes (P ≤ 0.05). **Means ± SD in the same column with the same letter are not significantly different (P ≤ 0.05).
greenness from 1.0 to 6.7 and yellowness from 1.2 to 8.0. These data agreed also with Soler-Rivas, Epsin, and Wichers (2000) who found that the panel evaluations of the appearance of different table olive treated with NaOH samples and showed that varieties had variations between the yellowness and greenness. They demonstrated that the main observed differences between the four different sensory profiles were due to the intensity values of fruit and seasoning. The results of aroma (Table 4) showed that there is no significant difference between de-bittering methods of fermentation, but the higher values of the briny, ocean-like, mushroom and vinegary were found in ticked followed by scratchy, treated with NaOH and whole, respectively. The higher values of mushroom were found in ticked followed by scratchy, treated with NaOH and whole, respectively; with some exception between treated with NaOH and scratchy that was no significant difference. The higher values of musty were found in scratchy followed by the whole and treated with NaOH and ticked, respectively, without significant difference. The higher values of soapy were found in treated with NaOH followed significantly by ticked, scratchy and whole, respectively, where is no significant difference between them. There was no significant difference between de-bittering methods of fermentation, but the higher values of earthy were found in ticked followed by scratchy, treated with NaOH and whole, respectively. The higher values of flora were found in scratchy followed significantly by the whole, ticked and treated with NaOH, respectively. Our results are agreed with Yilmaz and Aydeniz (2012) who reported that musty aroma ranged from 1.6 to 2.8, soapy aroma values from 2.8 to 3.6, but our results were higher than the range in vinegary from 1.9 to 2.9. The explanation as Soler-Rivas et al. (2000) reported that only treated with NaOH table olives data showed variation in the intensity values of odor and aroma attributes between the green table olives. They reported that these results could be related to the manufacturing process olives and developing a lactic fermentation over a more or less variable period of time. Also, they demonstrated that odor and aroma intensities are strongly influenced by the de-bittering method of fermentation. There are no studies with the other debittering methods of fermentation whole, scratchy and ticked table olives were found, but the explanation above could be applied to the other three investigated de-bittering methods.
The results of basic taste (Table 5) showed that there is no significant difference between samples, but the higher values of sour were found in whole followed by treated with NaOH, scratchy and ticked, respectively. The higher values of saltiness were found in ticked followed by scratchy, treated with NaOH and whole, respectively, with no significant difference. There is no significant difference between de-bittering methods of fermentation, but the higher values of hay were found in whole followed by scratchy, ticked and treated with NaOH, respectively. The higher values of bitterness were found in whole followed significantly by scratchy, ticked and treated with NaOH, respectively. The higher values of oily were found in scratchy followed by the whole, treated with NaOH and ticked, respectively, without significant difference. The higher values of buttery were found in whole followed significantly by ticked, scratchy and treated with NaOH, respectively. There is no significant difference between de-bittering methods of fermentation, but the higher values of ripeness were found in treated with NaOH followed by ticked, scratchy and whole, respectively. Our results are agreed and within Yilmaz and Aydeniz (2012) they found that sour taste value range 3.2 to 7.8, saltiness 3.0 to 5.8, bitterness from 1.2 to 3.3 and oily from 2.0 to 6.4. Also, the results of Soler-Rivas et al. (2000) are agreed with our results for only treated with NaOH table olives and the explanation is similar to what explained above.
The results of texture (Table 6) showed that the higher values of hardness were found in whole followed significantly by treated with NaOH, scratchy and ticked, respectively. The higher values of juicy moisture were found in ticked followed by scratchy, treated with NaOH and whole, respectively, without significant difference exist between samples. The higher values of crunchy were found in whole followed significantly by treated with NaOH, scratchy and ticked, respectively. The higher values of fibrous were found in whole followed Table 5. Descriptive sensory attribute scores of table olive varieties of descriptive panel after maturity.
significantly by treated with NaOH, scratchy and ticked, respectively. Our results are agreed and within Yilmaz and Aydeniz (2012) who investigated that hardness value ranged from 3.0 to 7.0, crunchy ranged from 5.0 to 7.5 and fibrous from 4.6 to 7.0. Galán-Soldevilla, Ruiz Pérez-Cacho, and Hernández Campuzano (2013) results also agreed and within our results, hardness and crunchy of table olive treated with NaOH were in a range of 4.5 to 6.2 and 5.1 to 7.4, respectively. Soler-Rivas et al. (2000) found that for only treated with NaOH table olive the values decreased in the firmness intensity; these results could be related to the manufacturing process olives are kept in brine until their delivery when they are fermented (Rababah et al., 2013).

Consumer testing
Consumer's opinions of fermented table olives are summarized in Tables 7 and 8. Hedonic scale results showed there were some significant differences (P < .05) between all de-bittering methods of table olive varieties for overall appearance, overall flavor, overall taste, overall texture, and overall bitter taste. The results of consumer testing in Table 7 showed that the higher values of overall appearance found in treated with NaOH followed significantly by the whole, scratchy and ticked, respectively. The higher values of overall flavor and taste found in treated with NaOH followed significantly by ticked, scratchy and whole, respectively. Also, the higher values of overall taste found in treated with NaOH followed significantly by ticked, scratchy and whole, respectively. Furthermore, the higher values of overall texture found in whole followed significantly by treated with NaOH, scratchy and ticked, respectively. The higher values of overall bitter taste found in whole followed significantly by, scratchy, ticked and treated with NaOH, respectively. Our results are agreed with Yilmaz and Aydeniz (2012) who studied only table olives treated with NaOH of different verities; they found that there were significant differences among the four samples for the consumer overall appearance values from 5.5 to 6.8, overall flavor values from 6.1 to 7.0 and overall taste values from 5.6 to 7.9. No reports in the literature were found regarding the consumer sensory characteristics of other different de-bittering methods of fermentation of table olive varieties; whole, scratchy, and ticked table olives.
Redness values ranged from 0.7 to 5.4 and the significantly highest value of a* parameter was found in whole followed by scratchy, ticked and treated with NaOH table olives, respectively. Fermentation is significantly affected the yellowness (b*) values, the range of b* values from 54.4 to 61.4. The higher a* value was found in treated with NaOH followed significantly by ticked, scratchy and whole table olives, respectively. Our results are agreed and within color measurements of Yilmaz and Aydeniz (2012) when fermentation completely finished for treated table olive with NaOH as below; lightness values ranged from 49 to 69.6, redness from 1.3 to 18.0 and yellowness from 19.5 to 45.5. They indicated that the explanation of this variation would be caused by the pigmentation differences of different genetic materials (Rababah, Hettiarachchy, Eswaranandam, Meullenet, & Davis, 2005). Also, Savas and Uylaser (2013) found that color scores were lower in olive treated with NaOH than in the other applications because of the lye pre-treatment. They also mentioned that color stability was negatively affected by this pre-treatment. The olives that were processed using scratching method had a straw color.
The results indicated that the olives treated with the lye solution were more sensitive to oxidation and darkened quickly when they were removed from the brine; the best color stability was obtained in the olives that were de-bittered using the scratching method. The color instrumental results regarding the four types of de-bittering methods of fermentation or the variety of table olives were agreed with both descriptive and consumer results (Tables 3 and 8).

Instrumental texture of table olives
Texture results for hardness (N) of all de-bittering method of fermented table olive varieties are shown in Table 8. As seen in Table 8, the hardness of all de-bittering method of fermented table olive varieties are varied and ranged from 1.7 to 4.2 N. The highest hardness values were found in whole followed significantly by treated with NaOH, scratchy and ticked table olives, respectively. Our results are agreed with Yilmaz and Aydeniz (2012) who reported that the texture by the end of fermentation ranged from 4.2 to 8.7 in treated with NaOH table olives. The explanation of these results could be due to the same reason of hardness in descriptive analysis. Overall, instrumental texture results were agreed with descriptive analysis and consumer results and showed that the fermentation period of storage decreased the hardness and produced soft products.

Conclusion
There were some differences in sensory parameters in comparison with the main table olives fermentation de-bittering methods. Instrumental texture results were agreed with descriptive analysis and consumer results. Sensory attributes for Baladi table olives have the most acceptable attributes. Despite of NaOH processing fermentation debittering method has the most sensory parameters but other investigated debittering methods still keeping high amount of sensory properties.