Determination of the tannins, pectins, hemicellulose, cellulose, nitrogen, mineral elements, total and reducing sugars and fat contents was carried out on carob pods from Mallorca, Spain. The results are compared with data from the literature. A survey of papers on the composition and practical applications of carob pods is included.

Components of nutritional interest in carob pods (Ceratonia siliqua)

Fusarium moniliforme was cultured semicontinuously on a carob medium in a 14-liter fermentor (8.5-liter working volume). The growth medium provided 2.4% carob sugar, 0.72% NH4H2PO4, and 0.03% MgSO4-7H2O. The biomass harvest was 8.8 g/liter per day. Ninety percent of the sugars were consumed, and the pH dropped from 5.9 to about 3.7. The crude protein (N X 6.25) of the spray-dried mycelium was 380 g/kg, 300 g/kg for the true protein (Lowry), and 4.8 g/kg for the (Folin-Denis) tannic acid. The mycelium was evaluated nutritionally with the weanling rat as experimental animal. The protein efficiency ratio and net protein utilization values for the unsupplemented mycelium were 1.15 and 0.42, respectively, and for the mycelium supplemented with DL-methionine (5 g/kg) they were 2.31 and 0.72, respectively. No growth depression was observed in the experimental rats, and on dissection of the carcasses the internal organs were found to be normal.

Growth of Fusarium moniliforme on carob aqueous extract and nutritional evaluation of its biomass.

SUMMARY The carob tree has great potential for restoring vegetation to degraded areas around the Mediterranean and other dry areas of the world, and for improving the productivity of lands which would be marginal for other crops. There is scope for utilising an increase in the bean harvest, by expanding the volume of existing products/uses, and by developing new products such as protein rich foods and fodders, sugar and syrup, industrial gums and alcohol. The paper includes a discussion of botanical characteristics of the carob tree and of the Mediterranean ecosystems in which it is found.

The potential of the carob (ceratonia siliqua)

Carob (Ceratonia siliqua L.), have wild and cultivated types, is an evergreen tree and widely grown in Mediterranean countries. Wild or cultivated carob has a high total dry weight content (approximately 91–92%) which primarily consist of sucrose, glucose, fructose, and also incorporate minor amounts of minerals, amino acids, and phenolic compounds. The seeds are generally used for the production of locust bean gum and the kibble is used to produce carob powder in western countries or “pekmez” in Turkey. Finding new carbon and nitrogen sources is important for lab-scale research to provide cheaper substrates for biotechnological processes to reduce costs. In this sense, carob is one of the important sources for any kind of fermentation processes with its rich nutritional ingredients. Carob pod extracts have been used in many lab-scale studies to produce ethanol, citric acid, lactic acid, mannanase, microbial cell protein, and other value-added products by yeasts, algae or fungi in recent years. In this review, we tried that organize all researches about carob pod extract fermentation to prove the suitability of carob pod for biotechnological processes.

Carob as a carbon source for fermentation technology

The kinetics of growth and the chemical composition ofFusarium moniliforme cultivated on aqueous carob pod extract were investigated. The extract was adjusted to provide 0.5, 1.0, 2.0 and 4.0% carob sugars supplemented with inorganic salts at the ratio: carob sugar: NH4H2PO4: MgSO4.7H2O=1:0.6:0.012. The extract contained 16 mg tannic acid (Folin-Dennis) per g of carob sugar. The phase of vigorous growth was exponential. Tannins were not observed to depress growth. The maximum value of 0.22 h−1 for a specific growth rate corresponding to a generation time of 3.15 h was obtained when the fungus was cultivated on a 4% carob sugar medium. The dry mycelium produced per g of consumed carob sugar was then 0.515 g. The protein and purine content was affected by the composition of the growth medium. Protein values up to 37.7% true (Lowry) and 53.1% crude (NX6.25) of dry mycelium were recorded. Mean purine contents were 89 and 116 μmol/g, corresponding to nucleic acid levels of 5.7 and 7.5% for mycelium grown on 0.5 and 4.0% carob sugar respectively. These findings linked with those previously reported regarding the good appearance and nutritional quality ofF. moniliforme (Drouliscos et al., 1976) make this fungus worthy of consideration for the production of protein.

Kinetics of growth and chemical composition ofFusarium moniliforme cultivated on carob aqueous extract for microbial protein production

The general scheme for microbial protein production (Gray, 1964, 1965, 1966) shows the conversion of green plant carbohydrates into fungal protein, which in turn can be converted to animal protein, which can then be used by man (GREEN PLANT CARBOHYDRATES ---+ FUNGUS PROTEIN --~ ANIMAL PROTEIN---+ MAN). We have already reported on the conversion of carob bean carbohydrates into fungal protein using the fungus Aspergillus niger, van Tieghem (Mitrakos et al., 1970). The carob bean sugars consist of a mixture of sucrose, glucose, fructose and maltose in a ratio of 5:1:1:0.7 (Mitrakos, 1968) and can be considered as a very good carbon source for fungal growth. In this paper we will present additional data on the growth of the fungus as well as the yield of dry mycelium and fungal protein under different nutritional conditions.

K. H. Sekeri-Pataryas

Papers

Yields of fungal protein from carob sugars