for morphological characterization; seeds have been extracted and evaluated in ... Fruits were collected in August from mature plants of 8 different accessions.
Morphological and Technological Characterization of Different Carob Cultivars in Sicily S. La Malfa, C. Avola, M. Brugaletta, G. La Rosa and G. Muratore Dipartimento di Scienze delle Produzioni Agrarie e Alimentari Università degli Studi di Catania Italy Keywords: Ceratonia siliqua L., biodiversity, seed, Mediterranean, LBG, thickening flour Abstract Carob (Ceratonia siliqua L.), is a legume tree species diffused in marginal dry areas of Mediterranean basin; carob tree has been long considered a neglected and underutilized species, but the crop is gaining popularity, since the flour extracted from the seeds (Locust Bean Gum, LBG) is used in food industry as thickening agent classified in the European Codex (E410). Nowadays several cultivars are cultivated in various Mediterranean countries showing high variability of morphological and technological properties of their fruits. Pods and seeds characterization appears to be important for the improvement of the business generated by carob products. For this reason 5 female (‘Ibla’, ‘Latinissima’, ‘Pasta’, ‘Racemosa’, ‘Ruta’) and 3 hermaphrodite genotypes (‘Ramillete’, ‘Sangimignana’, ‘Tantillo’) of different origin have been characterized. Fruits collected from mature plants have been used for morphological characterization; seeds have been extracted and evaluated in terms of yield, rheological properties, and sugar composition of the endosperm also in comparison with those of commercial samples coming from abroad. The viscosity of 1% LBG aqueous solutions was measured at different shear rates at pH 4.5 and 25°C. Results gave remarkable indications for some cultivars concerning seed number, weight and yield. LBG analysis of the samples showed statistical differences between the cultivars: the seeds of the Italian cultivars ‘Ibla’ and ‘Racemosa’ and those coming from Morocco showed the best yield, the latter standing out also for their high technological potential. The results confirm the high level of intraspecific variability in terms of seed yield, sugar composition of the endosperm, as well as thickening properties. INTRODUCTION Carob, Ceratonia siliqua L. (Fabaceae/Caesalpinioideae) is an evergreen tree, typical of the Mediterranean basin. This tree is an important part of Mediterranean natural vegetation and its cultivation in marginal and calcareous soils plays an important role under environmental and economical points of view. Spain, Italy, Morocco, Portugal and Greece produce about 90% of the world production (180.000 t). Italian production accounts for about 30.000 tons mainly obtained from south-east Sicily (FAOSTAT, 2008; La Malfa et al., 2008). Carob is exploited prevalently for the industrial transformation of the seeds, for obtaining a flour called locust bean gum (LBG; E 410), used as thickening agent in food preparations because of its ability to form viscous solutions and to stabilize emulsions and dispersion. Carob genetic resources are considered to be subjected to genetic erosion from Bioversity International (Batlle and Tous, 1997) mainly due to little knowledge of genetic resources, to poor economic value of the crop and for the absence of breeding programmes. In this picture, germplasm collection and characterization represent an important strategy for the maintenance of intraspecific biodiversity and for selection and breeding. Nowadays, several genotypes are cultivated in various Mediterranean countries Proc. XXVIIIth IHC – IS on the Challenge for a Sustainable Production, Protection and Consumption of Mediterranean Fruits and Nuts Eds.: A.M. D’Onghia et al. Acta Hort. 940, ISHS 2012
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showing high variability of morphological and technological properties of their fruits as shown in different studies carried out in the most important producing countries (Barbagallo et al., 1997; Tous et al., 2001; Barracosa et al., 2007; Konatè et al., 2007). At Catania University, cultivars and accessions coming from different Mediterranean countries have been collected and characterised (Caruso et al., 2008); recently collections and experimental fields have been established in order to evaluate selected genotypes in different cultivation areas. In this paper preliminary results of morphological and technological characterization are reported. MATERIALS AND METHODS Morphological Characterization Fruits were collected in August from mature plants of 8 different accessions cultivated in the south-east of Sicily: ‘Ibla’, ‘Latinissima’, ‘Pasta’, ‘Racemosa’ and ‘Ruta’ (females); ‘Ramillete’, ‘Sangimignana’ and ‘Tantillo’ (hermaphrodites). Among these accessions ‘Latinissima’ and ‘Tantillo’ are the most diffused cultivars in Sicily while ‘Ramillete’ is an important Spanish cultivar. A sample of 10 whole pods was taken for two consecutive years from the mass of fruits collected from each accession. Morphological analyses were conducted on these samples considering the following parameters: - length, width, thickness and fruit weight; - fertile and aborted seed number by fruit; - seed weight by fruit; - pulp/seed ratio; - length, width, thickness and seed weight. Technological Characterization Technological properties of LBG were determined for 12 samples among which 7 from the above cited accessions (‘Ibla’, ‘Latinissima’, ‘Pasta’, ‘Racemosa’, ‘Ramillete’, ‘Sangimignana’ and ‘Tantillo’) and 5 from commercial samples of different carob producing countries (S08 coming from Spain, S09 coming from Maillorca, Spain, T10 coming from Tunisia, T11 coming from Turkey and M12 coming from Morocco). The parameters measured were: - yield of germ and gum; - rheological properties; - sugar composition of the endosperm. Viscosity of 1% LBG aqueous solutions was measured at different shear rates at pH 4.5 and 25°C. Separation, identification, and quantification of monosaccharides and sucrose were performed by GC-FID by comparison with a mixture of standard sugars as reported in Rizzo et al. (2004). RESULTS AND DISCUSSION Morphological Characterization The morphological characterization showed a high level of variability for each carpological parameter considered (Table 1). The pods of ‘Pasta’ were those with the highest length and together with the ‘Ruta’ and ‘Ramillete’ ones resulted heavier than others. The cultivars ‘Pasta’ and ‘Ruta’ showed the heavier seeds and ‘Pasta’ also showed a higher number of seeds produced. ‘Ibla’, recently selected (La Malfa and La Rosa, 2006), gave the highest seed yield in terms of seed weight related with pulp weight of the pods collected. On the other hand the hermaphrodite cultivars ‘Ramillete’, ‘Sangimignana’ and ‘Tantillo’ showed the lowest values of seed yield. This result is due to the high weight of the fruits, just for ‘Ramillete’, while for ‘Sangimignana’ and ‘Tantillo’ the reason was the high number of aborted seeds and the low weight of the fertile ones (Fig. 1). 208
Technological Characterization LBG analysis of the samples showed statistical differences between the cultivars (Table 2); the seeds of the Italian cultivars ‘Ibla’ and ‘Racemosa’ (Fig. 2) and those coming from Morocco showed the best yield, the latter standing out also for their high technological potential (Fig. 3). CONCLUSIONS Because of the new interest towards this species, due to the properties of the flour extracted from the seeds (LBG), it is advisable to find the most reliable cultivars exploiting the existent germplasm. The results of the morphological and technological analysis performed on some accessions of Sicilian germplasm compared with foreign samples confirm the high level of intraspecific variability in terms of seed yield, of sugar composition of the endosperm and of thickening properties, too. Both characterizations suggest to promote the diffusion of the cultivars ‘Ibla’ and ‘Racemosa’ for the high seed yield, and consequently for germ and gum yield, considering their rheological properties too. The hermaphrodite cultivars, despite to the low level of seed yield, should be introduced in cultivation among female cultivars, in substitution of the male ones, for the vantages of their floral biology. For this reasons, among the hermaphrodite cultivars characterized, ‘Ramillete’ could be suggested for new orchards, considering the better performances shown. Literature Cited Barbagallo, M.G., Di Lorenzo, R., Meli, R. and Crescimanno, F.G. 1997. Characterization of carob germplasm (Ceratonia siliqua L.) in Sicily. J. Hort. Sci. 72(4):537-543. Barracosa, P., Osório, J. and Cravador, A. 2007. Evaluation of fruit and seed diversity and characterization of carob (Ceratonia siliqua L.) cultivars in Algarve region. Sci. Hort. 114:250-257. Batlle, I. and Tous, J. 1997. Carob tree, Ceratonia siliqua L. Promoting the Conservation and Use of Underutilized and Neglected crops, vol. 17. Institute of Plant Genetics and Crop Plant Research, Gatersleben. International Plant Genetic Resources Institute, Rome. Caruso, M., La Malfa, S., Pavlícek, T., Frutos Tomás, D., Gentile, A. and Tribulato, E. 2008. Characterization and assessment of genetic diversity in cultivated and wild carob (Ceratonia siliqua L.) genotypes using AFLP markers. J. Hort. Sci. & Biotec. 83(2):177-182. FAOSTAT. 2008. http://faostat.fao.org. Konate, I., Filali-Maltouf, A. and Berraho, E.B. 2007. Diversity analysis of Moroccan carob (Ceratonia siliqua L.) accessions using phenotypic traits and RAPD Markers. Acta Botanica Malacitana 32:79-90. La Malfa, S. and La Rosa, G. 2006. Ibla: una nuova selezione di carrubo. Rivista di Frutticoltura e di Ortofloricoltura 3:74-77. La Malfa, S., Brugaletta, M., Caruso, M., Gentile, A. and Tribulato, E. 2008. Iniziative di ricerca per la coltura del carrubo in Sicilia. Italus Hortus 15(3):40-48. Rizzo, V., Tomaselli, F., Gentile, A., La Malfa, S. and Maccarone, E. 2004. Rheological properties and sugar composition of Locust Bean gum from different carob varieties (Ceratonia siliqua L.). J. of Agricultural and Food Chemistry 52(26):7925-7930. Tous, J., Batlle, I., Rallo, J. and Romero, A. 2001. Prospección de variedades de algarrobo en las islas Baleares. Invest. Agr. Prod. Prot. Veg. 16(2):187-204.
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Tables Table 1. Morphological characterization of the analyzed accessions (mean ± s.e.; data are average of two years). Fruit length (cm) Pasta ♀ Ibla ♀ Ramillete ♀ Sangimignana ♀/♂ Tantillo ♀/♂ Racemosa ♀/♂ Ruta ♀ Latinissima ♀
Fruit width (mm)
Fruit thickness (mm)
Fruit weight (g)
Seed weight (mg)
Seed yield (w/w %)
22,9±1,7 24,8±1,3 8,8±1,0
33,4±3,9
230±11,2 10,6±1,4
19,5±1,1 19,3±1,2 6,8±0,7
13,7±1,9
194±8,7
16,9±2,4
18,7±1,3 25,3±1,9 12,8±1,0 37,9±6,4
210±20,2
6,4±1,9
17,6±1,4 22,7±1,7 9,9±0,7
25,6±3,5
168±18,5
4,9±1,7
17,0±2,0 24,7±2,2 10,4±1,7 24,0±4,8
157±12,5
6,4±1,6
15,8±2,3 24,6±2,1 10,6±0,8 25,2±4,9
180±15,8
9,5±1,7
15,3±1,4 26,8±1,8 14,0±1,3 33,3±5,3
234±29,4
6,8±1,8
14,9±1,2 23,5±1,3 10,3±0,8 21,5±3,3
206±13,5 10,0±0,8
Table 2. Relative humidity (RH), germ and gum yield of carob seeds of different origin. Sample Sangimigniana Ibla Racemosa Pasta Latinissima Tantillo Ramillete S08 S09 T10 T11 M12
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Origin Italy Italy Italy Italy Italy Italy Spain Spain Spain (Maillorca) Tunisia Turkey Morocco
RH (%) 6,41 8,06 7,6 5,73 7,25 7,71 7,84 8,57 9,72 6,12 5,95 7,14
Germ (% d.w.) 18,86 18,23 17,51 17,7 17,42 18,66 18,15 17,13 16,39 16,94 17,68 16,6
Gum (% d.w.) 49,1 54,01 52,41 51,03 47,43 42,26 32,07 51,61 49,28 51,87 43,2 53,78
Figurese
18
Fertile seeds (n)
Aborted seeds (n)
Number of seeds
15
12 9
6 3
0
Fig. 1. Number of seeds per pod.
Fig. 2. Pods of two cultivars.
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500 Sangimignana Ibla 400
Racemosa Pasta Latinissima
300
cps
Tantillo Ramillete 200
S08 S09 T10
100
T11 M12 0 10
20
30
rpm
50
60
100
Fig. 3. Viscosity values (centipoise) of 1% LBG aqueous solutions versus shear rate.
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