Dietary non-extractable condensed tannins as indigestible compounds: Effects on faecal weight,and protein and fat excretion

The possible degradation of non-extractable condensed tannins (NECT) within the intestinal tract and their effect on faecal weight and composition was studied. Two groups of male Wistar rats were fed either a NECT-free control diet, or a diet containing 100 g carob pod concentrate kg^?1 (53 g NECT kg^?1 dry matter) for 5 weeks. A slight effect of NECT on growth rate was observed in the fifth week. The NECT diet did not affect food intake. Significant increases of total faecal output as well as water, nitrogen and fat excretion were observed. NECT were not degraded in the intestinal tract, since they were quantitatively recovered in faeces (98 ± 1%). Since the usual spectrophotometric methods gave contradictory results on NECT levels in the diet and faeces, an alternative method based on Klason lignin residues was used.     

Composition and potential uses of mesquite pods (Prosopis pallida L): Comparison with carob pods (Ceratonia siliqua L)

The composition of mesquite pods (Prosopis pallida L) (PP), a legume cultivated in the large desert areas of Peru, was studied. These fruits have at the present time very little practical or commercial use. Taking into account the morphological and compositional similarities to Mediterranean carob pods (Ceratonia siliqua L) (CS), which are widely used in the food industry, some applications of PP are considered. PP shows better nutritional properties than CS, mainly owing to its lower polyphenolic content and higher protein digestibility.     

Mathematical modeling of batch bioethanol generation from carob extract in the suspended-cell stirred-tank bioreactor

In this study, various functions were evaluated and utilized to forecast observed values and kinetic parameters of the batch ethanol fabrication from carob extract in the suspended-cell stirred tank reactor (SCSTR). The best model was detected with the model comparison parameters (root-mean-square-error [RMSE], mean-absolute-error [MAE], and R²). The results indicated that the model Stannard (ST) successfully predicted biomass production data (RMSE = 0.26 g L⁻¹, MAE = 0.18 g L⁻¹, and R² = 0.9910), ethanol fabrication data (RMSE = 2.44 g L⁻¹, MAE = 1.88 g L⁻¹, and R² = 0.9809), and sugar depletion data (RMSE = 2.82 g L⁻¹, MAE = 2.17 g L⁻¹ and R² = 0.9938). Nevertheless, the lowest value of the objective function (Φ-factor) was also yielded as 0.041 using the model ST. Additionally, in the estimation of the kinetic data, the model ST also gave well-directed results. Besides, when an independent set of the observed values was utilized to confirm the mathematical functions, the satisfactory consequences were achieved in terms of both the experimental and kinetic values. Consequently, the model ST can work as a universal function in predicting observed values and kinetics of batch ethanol generation from carob extract in an SCSTR.     

Structural characteristics and rheological properties of locust bean galactomannans: a comparison of samples from different carob tree populations

Water‐soluble galactomannans were isolated from the seeds of 12 carob tree populations grown in different regions of southern Greece. Their structures, molecular weight distributions and rheological properties were examined. The intrinsic viscosity values and estimated average molecular weights varied in the ranges 8.15–13.02 dl g⁻¹ and (2.3–3.9) × 10⁶ respectively. Molecular sieve chromatography showed large variations in the molecular size distributions. The Manp/Galp ratio varied between 3.08 and 3.82, as determined by GC analysis of the alditol acetate derivatives of the monomeric constituents. There were also differences in the relative distribution of the free (Manp‐Manp), monosubstituted (Manp‐Manp(Galp)) and disubstituted (Manp(Galp)‐Manp(Galp)) dyads of β‐(1→4)‐mannose, as revealed by ¹³C NMR spectroscopy of the native polysaccharides. The pseudoplastic behaviour of galactomannan solutions (10–20 g l⁻¹) was confirmed by steady shear and dynamic rheological tests. Aqueous galactomannan (5 g l⁻¹)–xanthan gum (5 g l⁻¹) mixed systems gave gels on cooling (G′ ≫ G″). Galactomannans with high limiting viscosities, high Manp/Galp ratios and a low proportion of the Manp(Galp)‐Manp(Galp) dyad yielded the strongest mixed gel network structures with xanthan, implying that interchain associations between the two polymers occur via the unsubstituted segments (‘smooth regions’) of the carob galactomannan chains. © 2000 Society of Chemical Industry     

Effect of media sterilization and enrichment on ethanol production from carob extract in a biofilm reactor

In this study, repeated-batch fermentations in a biofilm reactor were evaluated for ethanol production from non-sterile enriched (NSE) and non-sterile non-enriched (NSNE) carob extracts by using Saccharomyces cerevisiae. For the NSE medium, the ethanol production (P) and yield (Y_P/S) were 18.46 g/L and 33.76%, respectively. However, for the NSNE medium, P and Y_P/S were 19.57 g/L and 38.14%, respectively. Results indicated that cost-effective ethanol production from non-sterile carob extract (NSCE) can be successfully applied in a biofilm reactor regarding both energy cost and recovery time.     

Continuous ethanol production from carob pod extract by immobilized Saccharomyces cerevisiae in a packed-bed reactor

The continuous production of ethanol from carob pod extract by immobilized Saccharomyces cerevisiae in a packed-bed reactor has been investigated. At a substrate concentration of 150 g dm^?3, maximum ethanol productivity of 16 g dm^?3 h^?1 was obtained at D = 0·4 h^?1 with 62·3% of theoretical yield and 83·6% sugars′ utilization. At a dilution rate of 0·1 h^?1, optimal ethanol productivity was achieved in the pH range 3·5–5·5, temperature range 30–35·C and initial sugar concentration of 200 g dm^?3. Maximum ethanol productivity of 24·5 g dm^?3 h^?1 was obtained at D = 0·5 h^?1 with 58·8% of theoretical yield and 85% sugars′ utilization when non-sterilized carob pod extract containing 200 g dm^?3 total sugars was used as feed material. The bioreactor system was operated at a constant dilution rate of 0·5 h^?1 for 30 days without loss of the original immobilized yeast activity. In this case, the average ethanol productivity, ethanol yield (% of theoretical) and sugars′ utilization were 25 g dm^?3 h^?1, 58·8% and 85·5%, respectively.     

Matrix composition effect on the digestibility of carob flour phenols by an in-vitro digestion model

Carob flour (CF) and washed carob flour (WCF) (without the water soluble dietary fraction) were submitted to an in-vitro digestion method to evaluate the dietary soluble fibre (DF) and soluble sugars content on the digestibility and bioaccessibility of polyphenols. In addition, combinations of the raw materials (CF and WCF) with hazelnut oil (HO) were proposed in order to evaluate the protection of a vegetable oil rich in polyunsaturated fatty acids (PUFA) on the phenolic compounds submitted to in-vitro digestion conditions. The results showed that the soluble dietary fraction enhanced the stability of the phenolic compounds during the duodenal digestion phase. Similarly, the lipid fraction (rich in PUFA) showed a protective effect on the recovery of the phenolic compounds during duodenal digestion. Disruption of the natural matrix under digestion conditions led to the release of DF and PUFA, which could establish interactions with certain polyphenol compounds enhancing their recovery and stability during digestion.     

Oviposition stimulants of the mothEctomyelois ceratoniae: The effect of short-chain alcohols

Females of the mothEctomyelois ceratoniae prefer to oviposit on carobs,Ceratonia siliqua L., infested with the fungusPhomopsis sp. (Gothilf, 1964). An extract of the steam distillate of fungus-infested carobs was more effective in stimulating female moths to oviposit than was an extract of uninfested carobs. The extract of the fungus-infested carobs was found to be composed mainly of simple alcohols: ethanol (60%),n-propanol3 (15%), 2-propanol (2.5%), isobutanol (15%),n-butanol (2.5%), and isopentanol (5%). In addition, the extract contained a small proportion (1–2%) of unidentified compounds. All of the alcohols, with the exception of isopentanol, stimulated oviposition by female moths. However, the alcohols, when tested separately or as a mixture, were not as stimulating as the total extract. The unidentified compounds were less stimulating than the alcohols.     

Performance comparison of precipitation strategies for recovering succinic acid from carob pod-based fermentation broths

ABSTRACT

Experiments were performed for comparing and selecting the most appropriate precipitation strategy for succinic acid (SA) recovery from carob pod extract fermentation broths. The performances of three downstream options – employing calcium hydroxide, magnesium hydroxide or ammonia – were investigated and compared from operational, techno-economical and sustainability viewpoints. The highest SA recovery (84.3%) was obtained with ammonia, whereas the calcium-based treatment proved inadequate. Sustainability indicators favoured magnesium-based treatment, closely followed by the ammonia-based one. A preliminary economic analysis favours magnesium-based treatment, which appears to be the most feasible option. However, materials recycling and possible by-products commercialization could well position also ammonia-based treatment.