New multiresistant apple cultivars - Complex assessment of sensory and some instrumental attributes

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Acta Alimentaria, Vol. 42 (2), pp. 132–142 (2013) DOI: 10.1556/AAlim.42.2013.2.14

NEW MULTIRESISTANT APPLE CULTIVARS – COMPLEX ASSESSMENT OF SENSORY AND SOME INSTRUMENTAL

ATTRIBUTES

l. siposa*, G. Ficzekb, Z. kókaia and M. TóTHb

aSensory Laboratory, Faculty of Food Science, Corvinus University of Budapest, H-1118 Budapest, Villányi út 29-43. Hungary

bDepartment of Pomology, Faculty of Horticultural Science, Corvinus University of Budapest, H-1118 Budapest, Villányi út 29-43. Hungary

(Received: 25 April 2012; accepted: 6 December 2012)

Our study involved assessing new Hungarian multiresistant apple cultivars (‘Artemisz’, ‘Hesztia’, ‘Rosmerta’, and ‘Cordelia’) and two commercial cultivars (‘Watson Jonathan’ and ‘Prima’). The samples were evaluated by a trained assessor panel applying computer supported profile analysis with 20 descriptive sensory parameters (using ProfiSens sensory assessment software). Beside the profiles of each cultivar we also showed the significant differences between the cultivars (LSD95%, LSD99%). The nutritional values were analysed using the MANOVA statistical method, the effects of significant factors on measured values were evaluated by using Tukey (P=0.005) post hoc test, and we determined the homogenous and heterogenous groups based on that. Our study showed that PCA bi-plots containing sensory and instrumental value loadings together with the scores of apple cultivars make the complex relationships of each cultivar available for comparison. The results clearly showed that the intensity of the sour taste is inversely proportional to the carbohydrate–acid ratio determined by measurements. The flesh firmness and pectin content values obtained by instrumental measurements were found to be strongly correlated sensory parameters on crispness, texture, and ripeness. PCA plots proved to be very useful in demonstrating the parallelisms between instrumental-instrumental (TPC/FRAP) and sensory-sensory (shade/colour) parameter pairs, too. Our aggregated results show that the new Hungarian resistant apple cultivars have almost as good as or even better nutritional values than ‘Prima’ and ‘Jonathan’ (the latter dominated the Hungarian apple production for several decades). The new multi-resistant cultivars renew the range of apple cultivars available on the market, and they introduce new flavours to consumers.

Keywords: multi-resistant apple cultivars, profile analysis, Total Phenol Content (TPC), Ferric Reducing/Antioxidant Power (FRAP), Principal Component Analysis (PCA)

Apple is the most significant fruit of the temperate zone, and it plays a vital role in a healthy diet. Many life science studies proved the health-conserving and recuperative effects of consuming apples (liu, et al., 2001; lee & cHan, 2011). As a result of globalization, the number of apple cultivars was reduced in both the international market trade and industrial usage to such an extent that today the accumulated apple production is dominated by just a few global apple cultivars (or apple groups). These cultivars are susceptible to the most common apple diseases, so their production requires intensive use of high-cost chemicals as a means of protection. Experts dedicated to maintaining biodiversity, widening the consumers’ product range, and protection of environment and health, are determined to change this tendency to use global cultivars. It is a vital task to define differentiated use of cultivars based on geographical regions so that a unique portfolio of apple cultivars can be provided in each

* To whom correspondence should be addressed. Phone: (+36-1) 482-6452; fax: (+36-1) 482-6326; e-mail: [email protected]

133SIPOS et al.: PROPERTIES OF NEW MULTIRESISTANT APPLE CULTIVARS

Acta Alimentaria 42, 2013

country, and this portfolio can satisfy the new demands of consumers as well (like safe, chemical-free product, high quality, and favourable nutritional value with active biological agents).

The Department of Pomology of the Corvinus University of Budapest has started an apple breeding program (TóTH, 2005) that was focused on resistance to several diseases (multi-resistance), on quality, and on special characteristics. The efforts lead to four officially acknowledged cultivars in 2011 and 2012 (‘Artemisz’, ‘Hesztia’, ‘Rosmerta’, and ‘Cordelia’), while the program makes it possible to re-new the range of tastes and apple cultivars in Hungary and in Europe. This was the first step in the creation of a range of multiresistant apple cultivars that meet the demands in the 21st century and fit the ecological characteristics of the Carpathian basin.

1. Materials and methods

1.1. Materials

The material for the study was provided by a plantation in Soroksár managed by the Experimental and Research Farm of the Faculty of Horticulture (Corvinus University of Budapest). Apple cultivars were hand-picked at their optimal ripeness, from 4 trees per cultivar, with a minimum of 3 kg fruit from each cultivar. We took special care to pick fruits with homogeneous exterior characteristics. Our experiments were carried out involving new native multiresistant apple cultivars (‘Artemisz’, ‘Hesztia’, ‘Rosmerta’, and ‘Cordelia’) and commercial apple cultivars (‘Watson Jonathan’ and ‘Prima’), too. The four new cultivars were resistant against all the most important apple diseases (apple scab, powdery mildew, and fire blight). Scab resistance is controlled by the Vf gene originating from the species Malus floribunda 821 and transmitted by cultivar Prima. Heterozygote Vfvf genotype of the cultivars was proved by molecular genetic examinations (TóTH, 2005).

Artemisz: Open-pollinated seedling of ‘Prima’. Ripens in early or middle September. Fruit size is medium to large (140–200 g), shape is round conic. Suitable for processing (apple chips, juice, and concentrate), as well as for fresh consumption after storage for those who like acidic apples. Its green ground colour is covered by an intense red or claret cover colour on the total fruit surface, gradually darkening with ripening, and this combines with dissolving bloom and rare but conspicuous white dots. Pedicel is short or medium long, pedicel hole is sometimes burned. Calyx and ovary are both closed. Its flesh keeps its outsanding firmness during storage. Flesh is white, juicy, taste is sweet-acid, aromatic.

Hesztia: Open-pollinated seedling of ’Prima’. Ripens in early September, fruit size is medium, average weight is 180–250 grams, shape is slightly oblate, true conic. As a nice autumn apple, it is recommended for fresh consumption till December. Its yellowish white ground colour is overlaid on great part of fruit surface, the showiness of which is increased by a slight bloom and presence of small white lenticells. Pedicel is short or medium long, calyx is closed or half-open, ovary is totally closed. Flesh remains outstandingly firm during storage. Flesh colour is light-yellow, taste is harmonic, combined with a tender aroma.

Rosmerta: Hybrid of ‘All Red Jonathan’ and ‘Prima’. Optimal harvest time is middle of September, fruits are rounded oblate, medium size, average weight is 140-150 grams. Resembling to Jonathan, it is recommended for fresh consumption and for processing as well. The yellowish green ground colour is covered by a bright red overlay on most of the fruit surface. Its cream coloured fruit flesh is medium firm. Pedicel is medium long, both

134 SIPOS et al.: PROPERTIES OF NEW MULTIRESISTANT APPLE CULTIVARS


calyx and ovary are closed. Its acidic sweet taste based on harmonic inner values and high polyphenol content is riched by a pleasant aroma. It has high level resistance to scab, moderate resistance to powdery mildew and fire blight.

Cordelia: Originates from the crossing of ‘Prima’ and ‘Granny Smith’. It can be harvested in early October and can be consumed after 2–3 months of storage. The fruit is very large, shape is rounded elongated, widest at the middle. First a light pink, then a bright red covering develops on its yellowish green groud colour during ripening. Cover colour is washed or striped, and usually does not cover the whole fruit surface. The surface is spotted by quite densely placed lenticells of medium size. Its pedicel is medium long. It keeps its high flesh firmness values even during storage. Fruit flesh is cream coloured, juicy, taste is nicely sweet-acidic. Receptacle hole and closed ovary are perigynous.

1.2. Methods

1.2.1. Computer supported profile analysis method. The experiment was designed and conducted, and the results were evaluated in compliance with the standard ISO (1994). The leader of assessors’ panel outlined the goal of the sensory evaluation, the core elements of the method, and the tasks to be carried out by the team. All assessors were trained, and each of them received a sample sequence labeled with identical, random-generated 3-digit codes (in compliance with the international practice). Assessors created a list of all detected sensory characteristics individually while still inside the assessor cabin. Then in teamwork they identified (following the so called ‘group consensus method’) the group of characteristics that all assessors clearly detected and noted. Doing so they determined the elements of the assessment system to which they assigned an evaluating method as well. Each assessor evaluated the samples using assessment sheets and prepared samples, and rated the samples by the characteristics determined with the group consensus method. Assessors consumed mineral water with neutral characteristics between tasting samples to neutralize sensory interferences (sipos, 2009).

We used the function specific, Excel-based software ProfiSens that was programmed in Visual Basic by researchers working at the Department of Biochemistry and Food Technology (changed recently to Department of Applied Biotechnology and Food Science) of Budapest University of Technology and Economics (BUTE), and researchers working at the Sensory Assessment Laboratory of the Corvinus University of Budapest (CUB). The software is capable of publishing and collecting assessment forms over a local network, then its processing and evaluating module carries out statistical calculations providing real-time results. The software determines the mean values and the mean-square deviations, and then it runs a univariate variance analysis on the data. If a significant difference was found at a certain sensory attribute, we used the paired Fischer method LSD95%, LSD99% (kókai et al., 2004). The correlation between sensory attributes and the correlation between sensory and instrumental results were analysed by PCA using PanelCheck software (MeulleneT et al., 2007; daHl et al., 2008).

Sensory tests were carried out at the Sensory Assessment Laboratory of the Corvinus University of Budapest (CUB). A laboratory complies with the international standards, and the assessment conditions are kept constant. The sensory laboratory was designed in compliance with ISO (2007) containing separated cabins and providing means of electronic data collection. Each assessment cabin is isolated from the others, it has a window to receive samples, it also has running water tap, and a computer connected to a local area network. The unbiased sensory assessment and detailed description of different apple cultivars was carried



out by trained sensory assessors. The assessment panel had 11 members, and were chosen and trained in accordance with the standard ISO/DIS (2011). Prior to the evaluation all assessors took part in a training to be able to detect all the important sensory parameters.

1.2.2. Instrumental measurements. Instrumental measurements were carried out in the laboratories of the Department of Pomology. The size and weight parameters of all average samples were measured and the values of refraction and titration acidity were determined as soon as the samples were received. Spectrophotometric measurements were made on crushed fruit pulp that was stored deep-frozen until the measurements. After the thawing of the samples the pectin contents, polyphenol contents, and water-soluble antioxidant capacities were determined by carrying out 3 measurements for each parameter.

Fruit size parameters (maximum diameter and height) were determined in millimeters using Mitutoyo CD-15DC digital calliper connected to a PC. The weight of the fruits analysed was measured using a KPZ-2-05-4/6000 digital scale. The firmness of apple samples was measured by the commonly used Magness-Taylor manual penetrometer equipped with a 11.1 mm probe head. We removed an area of the skin of the evaluated apple cultivars at the two endpoints of the maximum diameter on both the sunny side (with intense colour) and the shadowed size (less intense colour) so that it would not hinder the 11.1 mm probe head of the penetrometer penetrating the flesh. The resistance value (kg cm-2) of the fruit flesh against the probe head at a 0.5 cm penetration depth was measured.

The water-soluble dry matter content was determined using an ATAGO PR-101 digital refractometer in compliance with the specifications of CodeX AliMenTarius (1993). Total titration acid-content was determined using 0.1M NaOH solution and phenolphthalein indicator in accordance with the Hungarian standard MSZ EN (1998). The pectin content was determined using the method of kyriakidis and psoMa (2001). After sulphuric acid digestion the absorbance of samples at λ=525 nm was measured using a Hitachi U-2800 spectrophotometer. The polyphenol content was measured using spectrophotometry at λ=765 nm wavelength in the presence of Folin-Ciocalteu reagent, evaluating the results by a tannic acid calibration curve following the method of sinGleTon and rossi (1965). The ferric reducing/antioxidant power (FRAP) assay was carried out according to Benzie and sTrain (1996). The FRAP assay is based on the reduction of the Fe3+-2,4,6-tripyridyl-S-triazine complex to the ferrous form (Fe2+) and the intensity of the reaction is monitored by measuring the change of absorption at λ=593 nm.

The nutritional values were analysed using the MANOVA statistical method, the effects of significant factors on measured values were evaluated by using Tukey (P=0.005) post hoc test, and the homogenous and heterogenous groups were determined based on that. Relationships between products, sensory attributes, and instrumental measurements were determined by the PCA method after standardization. We used standardized PCA correlation loading plot (PanelCheck) to analyse the correlation between sensory and instrumental results (naes et al., 2010).

2. Results and discussion

2.1. Results of the computer supported profile analysis method

The trained panel of assessors defined 20 descriptive sensory characteristics and they evaluated the samples on a 0–100 point, unstructured scale. Thirteen of these characteristics showed significant (minimum LSD95%) difference between the cultivars assessed: shade of



colour red, red colour coverage, yellow colour coverage, patternization, size, shape, shape symmetry, texture, ripeness, skin toughness, intensity of acerbity, after-taste, and crispness. The sensory similarity of the samples lead to insignificant differences at the following product parameters: shade of colour yellow, shade of colour green, green colour coverage, colour of fruit flesh, intensity of apple odour, juicyness, and intensity of sweetness. The aggregated sensory profile diagram shows all the sensory parameters of the different cultivars below (Fig. 1). The paired LSD-values of taste and texture parameters of the cultivars assayed can be found in Table 1.

-1.5-1

-0.50

0.51

1.5

2shade of colour red

red colour coverage

shade of colour yellow

yellow colour coverage

shade of colour green

green colour coverage

patternization

size

shape

shape symmetrycolour of fruit flesh

intensity of apple odour

texture

ripeness

juicyness

skin toughness

intensity of sweetness

intensity of acerbity

after-tastecrispness

Fig. 1. Sensory profiles of the examined apples cultivars. : Artemisz; : Cordelia; : Rosmerta; : Prima; : Hesztia; : Watson Jonathan

The relationship between an apple cultivar and its sensory parameters can be analysed further using PCA bi-plot. Plotting scores and loading plots in the same diagram makes it possible to analyse the relative position of sensory characteristics and cultivars. The Principal Component Analysis showed a 66.1% explained variance at the first principal component, and another 15.5% at the second. The two PCs account for 81.6% of the explained variance. The sensory parameters positioned close to a certain cultivar are closely related characteristics, and the significance of the parameters decrease proportionally with the distance (Fig. 2).

2.2. Results of the instrumental measurements

The cultivars involved in the assay showed considerable differences in size: cultivars ‘Watson Jonathan’ (150 g) and ‘Prima’ (156 g) have small average size, cultivars ‘Rosmerta’ (171 g), ‘Artemisz’ (187 g), and ‘Hesztia’ (199 g) have a medium average size, while ‘Cordelia’ (262 g) has a large average size.



Table 1. Significant differences of the important taste and texture attributes in case of the examined apples cultivars

Texture*ripeness **skin toughness***intensity of acerbity****after-taste*****crispness******

Artemisz (MR-03)

Rosmerta (MR-09)

Hesztia(MR-10)

Cordelia(MR-12)

Prima WatsonJonathan

Artemisz (MR-03)

− nonenone

P=0.01nonenonenone

nonenonenonenonenonenone

P=0.01P=0.05nonenonenone1%

nonenonenone

P=0.05P=0.05none


Rosmerta (MR-09)

0.59.819.412.93.111.4

− nonenone

P=0.05nonenonenone

P=0.01P=0.01nonenonenone

P=0.01

nonenone

P=0.01nonenonenone

nonenone

P=0.01P=0.05nonenone

Hesztia(MR-10)

6.34.61.510.05.10.1

5.85.117.92.92.011.5

− P=0.01P=0.01nonenonenone

P=0.01


nonenone

P=0.05P=0.05nonenone

Cordelia(MR-12)

23.016.48.90.45.621.6

23.526.110.513.38.833.0

29.321.07.410.410.821.5

− P=0.01P=0.05P=0.05P=0.05P=0.01P=0.01

P=0.05P=0.05P=0.01nonenone

P=0.01

Prima 2.91.56.317.114.99.9

2.48.325.64.311.81.5

3.43.17.87.19.810.0

25.917.915.117.520.531.5

− nonenonenone

P=0.01P=0.01none

WatsonJonathan

1.83.113.08.37.96.0

2.36.632.421.111.05.4

8.01.514.518.313.06.1

21.319.521.97.92.327.6

4.61.66.825.422.83.9

−

* Sd(5%)=16.24 Sd(1%)=21.71; ** Sd(5%)=15.23 Sd(1%)=20.36; *** Sd(5%)=14.24 Sd(1%)=19.04; **** Sd(5%)= 16.27 Sd(1%)=21.76; ***** Sd(5%)=13.72 Sd(1%)=18.34; ****** Sd(5%)=15.81 Sd(1%)=21.14

Of all the cultivars involved in the assay, ‘Prima’ was found sweetest having the highest carbohydrate-acid ratio (22.84). ’Watson Jonathan’ (19.3), ‘Rosmerta’ (19.55), and ‘Cordelia’ (20.93) were found to be less sweet, and no significant difference was detected between the intensity of their sweetness. The cultivars with the sourest taste were ‘Artemisz’ (14.84) and ‘Hesztia’ (16.02). Cultivars showing the lowest fruit firmness were ‘Prima’ (6.29 kg cm-2) and



‘Rosmerta’ (6.25 kg cm-2). Higher flesh firmness was found for ‘Artemisz’ (7.61 kg cm-2), ‘Hesztia’ (7.32 kg cm-2), and ‘Watson Jonathan’ (7.28 kg cm-2), where the similarity of values could be shown by statistical methods, too. The cultivar with the highest value of firmness was ‘Cordelia’ (at 8.39 kg cm-2).

Fig.3.

Fig. 2. Standardized PCA bi-plot of the examined apple cultivars and sensory attributes

The firmness of fruit flesh and the pectin content are closely related as the firmness is provided by the pectin substances within the cell walls. Our results show that the highest pectin content (0.78%) was measured in the high-firmness ‘Cordelia’ samples, while the second highest pectin content was measured in ‘Prima’ (0.65%). Significantly lower pectin contents were found in the other samples: ‘Artemisz’ (0.51%), ‘Rosmerta’ (0.54%), ‘Hesztia’ (0.46%), and ‘Watson Jonathan’ (0.44%).

Considerable differences were detected in the polyphenol content and water-soluble antioxidant content (FRAP) of the cultivars. The lowest polyphenol content was measured in ‘Watson Jonathan’ samples (107.36 mg GAE/l), and the second lowest value was found in ‘Artemisz’ apples (145 mg GAE/l). They were followed by ‘Hesztia’ (206 mg GAE/l) and then two cultivars with similar polyphenol content: ‘Rosmerta’ (286 mg GAE/l) and ‘Prima’ (310 mg GAE/l). ‘Cordelia’ contained an outstandingly high level of polyphenols expressed as gallic acid equivalent (348 mg GAE/l). The water-soluble antioxidant capacity graph of the apple cultivars showed similarities with the polyphenol content. The lowest FRAP value expressed as ascorbic acid (AA) was measured in ‘Watson Jonathan’ samples (104.89 µg AA/ml) and ‘Artemisz’ samples (104.24 µg AA/ml). An outstandingly high level of water-soluble



antioxidant capacity was measured in ‘Cordelia’ apples (257.27 µg AA/ml) – just like with the polyphenol content. All the nutritional value averages, deviations, and the homogenous and heterogenous groups (MANOVA, Tukey P=005) can be found in Table 2.

Table 2. Results of instrumental measurements

Artemisz (MR-03)

Rosmerta (MR-09)

Hesztia(MR-10)

Cordelia(MR-12)

Watson Jonathan

Prima

Weight (g/pc) 187.2±13.08 b

171.6±18.05 ab

262.0±12.6 c

199.6±12.56 b

150.9±26.1 a

156.5±2.55 a

Firmness (kg cm-2) 7.61±0.046 ab

6.25±0.27 a

8.39±0.29 b

7.32±0.83 ab

7.28±0.29 ab

6.29±1.66 a

Refraction (%) 14.23±0.25 b

13.49±0.83 b

13.3±0.31 b

14.65±1.13 b

14.09±0.62 b

11.88±0.97 a

Titration acidity (%) 0.96±0.02 c

0.69±0.07 b

0.83±0.02 bc

0.70±0.01 b

0.73±0.02 b

0.52±0.12 a

Carbohydrate/Acid 14.82±0.11 a

19.55±1.4 ab

16.02±0.76 a

20.93±1.48 ab

19.30±0.23 ab

22.84±5.4 b

Pectin (%) 0.51±0.14 a

0.54±0.01 ab

0.78±0.04 c

0.46±0.05 a

0.44±0.01 a

0.65±0.06 bc

TPC (mg GAE/l) 145±9.65 b

286±5.02 d

206±6.38 c

348±15.82 e

107.36±15.07 a

310±16.07 d

FRAP (µg AA/ml) 104.24±2.19 a

128.51±0.89 b

117.02±3.56 ab

257.27±9.4 d

104.89±2.19 a

190.32±9.4 c

2.3. Relationships between sensory and instrumental results

PCA correlation loadings diagrams can provide direct data on how well the sensory variables can be explained by various instrumental parameters. The outer ellipse of the PCA correlation loading plot represents the 100% explained variance, while the inner ellipse represents the 50% explained variance level. Our results showed that there was a strong correlation between the sensory values and the instrumental values for sourness. The carbohydrate–acid ratio measured and the intensity of the sour taste showed inverse relationship as the two variables are located on the opposite side of the circle as if they were mirrored. The firmness and the pectin content values determined by instrumental measurements have higher correlation with crispness, texture, and ripeness. PCA diagrams also show the connection between instrumental-instrumental and sensory-sensory parameter pairs, too. Examples for such pairs are the colour coverage for red and yellow (sensory) or the values for polyphenol and FRAP (instrumental) (Fig. 3).

The only goal of using PCA is to identify high variance directions, so we standardized all the sensory and instrumental data so that the relatively higher variance of some variables would not distort the final results. By using a PCA bi-plot displaying the scores of the product together with the sensory and instrumental values, it is possible to analyse the more complex relationships of the cultivars. This method provides us additional data when compared to PCA correlation loading plots. According to the diagram, the key characteristics of ‘Cordelia’ are: large weight, large size, high firmness, hard flesh texture, crispness, and balanced carbohydrate–acid ratio. The most important parameters of ‘Hesztia’ and ‘Rosmerta’ are:



Fig. 3. Correlations between sensory and instrumental data by standardized PCA correlation loadings

Fig. 4. Correlations between apples cultivars, sensory attributes, and instrumental parameters by standardized PCA bi-plot



shade of colour yellow, yellow colour coverage, apple odour, symmetry of shape, patternization, high pectin content, and balanced carbohydrate–acid ratio. While ‘Prima’ is characterized by a carbohydrate–acid ratio shifted towards sweetness, ‘Watson Jonathan’ apples are rather sour, and their after-taste parameter is dominant. ‘Artemisz’ is unique amongst the cultivars assayed in that it has relatively high refraction values together with high acid content (Fig. 4).

3. Conclusion

The apple breeding program started by the CUB Department of Pomology in the early 1990s focused on combining resistance towards apple scab with resistance towards powdery mildew and fire blight so that the resulting multiresistant fruit is of high quality, has high yields, and withstands long storage periods. Our study assayed new apple cultivars (‘Artemisz’, ‘Hesztia’, ‘Rosmerta’, and ‘Cordelia’) bred as part of this program, and some commercial cultivars (‘Watson Jonathan’ and ‘Prima’). The sensory parameters of the cultivars assayed were evaluated by a trained assessory panel using computer supported profile analysis that provided data on the descriptive sensory profiles of each cultivar plus the significant differences (LSD) between paired taste and texture parameters.

The size, the carbohydrate–acid ratio, and the flesh firmness are key parameters along which consumers rate fruits. Our instrumental measurements showed considerable differences in size. ‘Cordelia’ showed outstandingly large size (262 g), while other new cultivars were of medium size. The taste of apples (and so the consumer experience) is mainly determined by the ratio of their sugar and acid content, and the firmness of the flesh plays an important role, too. Of all the cultivars only ‘Prima’ had its carbohydrate–acid ratio (22.84) a bit on the sweet side. ‘Rosmerta’ and ‘Cordelia’ had more balanced carbohydrate–acid ratio. The highest flesh firmness value was measured in ‘Hesztia’ samples (8.39 kg cm-2), the cultivars with the lowest firmness values were ’Prima’ (6.29 kg cm-2) and ‘Rosmerta’ (6.25 kg cm-2). The cultivars assayed showed considerable differences between polyphenol contents and water-soluble antioxidant content (FRAP). The lowest polyphenol and antioxidant levels were found in the fruit of ‘Watson Jonathan’, while exceptionally high levels of polyphenol and water-soluble antioxidants were measured in ‘Cordelia’, and high polyphenol content was detected in ‘Prima’ and ‘Hesztia’.

Correlations between sensory and instrumental data showed that the intensity of sour taste and the carbohydrate–acid ratio determined by measurements showed and inversely proportional relation (just as expected). We managed to confirm the results of previous assays that showed strong correlation between firmness and pectin content (both determined by instrumental measurements) analysed together with sensory attributes texture, crispness, and ripeness. Pectins create bonds with other cell-building substances (e.g. cellulose, and hemicellulose) increasing the mechanical stability and flexibility of the cell-walls (Mccann & roBerTs, 1991). Pectin substances have a significant role in defining fruit flesh texture (yosHiokA, et al., 1992; serGuscHenko et al., 2007). Our study showed that PCA bi-plots containing sensory and instrumental values together with the scores of apple cultivars make the complex relationships of each cultivar available for comparison. For instance, the most important attributes of ‘Cordelia’ are the following: large weight, large size, high flesh firmness, hard texture, crispness, ripeness, and balanced carbohydrate-acid ratio.



Summarizing our results: the new Hungarian resistant apple cultivars have almost as good as, or even better nutritional values than ‘Prima’ or ‘Jonathan’ (the latter dominated the Hungarian apple production for several decades). Based on these results we found that the new multiresistant cultivars cost less to produce (requiring much less chemicals) and are clearly recommendable to widen the range of available products and to replace ‘Jonathan’. We plan to measure the consumers’ response in a representative prevalance survey on consumer preferences.

*

This project was supported by TÁMOP-4.2.1/B-09/1/KMR-2010-0005 ‘Improvement of quality of higher education through research-development, innovation, and education development’ project.

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New multiresistant apple cultivars - Complex assessment of sensory and some instrumental attributes

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