Sucrose supplementation during traditional carob syrup processing affected its chemical characteristics and biological activities

Identification, Bioaccessibility, and Antioxidant Properties of Phenolic Compounds in Carob Syrup

Carob syrup is a brown, thick syrup produced from carob pulp that can be directly consumed or used as a sweetener, which also finds applications in folk medicinal practices. In this work, the quali-quantitative phenolic profile of five different carob syrups was elucidated before and after in vitro gastro-intestinal digestion. Moreover, the anti-oxidant properties of undigested and digested carob syrups were investigated. A total of 75 phenolic compounds were identified in undigested carob syrups. The most important phenolic compound in all the samples was gallic acid, the concentration of which ranged between 54.28 and 117.73 mg/100 g. Additional compounds belonging to the classes of hydroxybenzoic acids (in particular glycosylated gallic acid derivatives), hydroxycinnamic acids, and flavonoids (especially flavonols) were also identified. During in vitro gastric digestion, gallic acid mono- and di-hexosides were diglycosylated, releasing gallic acid, which was further degraded in ellagic acid through oxidative polymerization in the intestinal phase of the digestion. Ellagic acid was the major compound detected after in vitro gastro-intestinal digestion of carob syrups. With few exceptions, the anti-oxidant properties of carob syrup were preserved even after digestion. Carob syrup can be considered an important source of phenolic compounds with demonstrated positive effects on human health.

Optimizing prickly pear by-product valorization: formulating molasses with enhanced antioxidant capacities and sugar contents

This study endeavoured to capitalize on prickly pear by-products for the optimization of molasses formulation, targeting elevated antioxidant capacities and superior sugar contents. Through robust statistical modelling, the optimal cooking parameters-temperature (70-80 °C) and duration (60-90 min)-were determined, guided by responses of antioxidant activity and Brix value. A D-Optimal mixture design further delineated the ideal proportions of molasses components (pulp, peel, and seeds). Characterization revealed that peel harboured the highest concentrations of total polyphenols (396.41 mg GAE/100g FW) and flavonoids (234.26 mg CE/100g FW), emphasizing its antioxidant potential (DPPH inhibition IC50: 12.72 µg/ml). The optimal cooking conditions were established at 78.35 °C for 79.70 min, with predictive equations guiding ingredient proportions (0.265 g pulp, 0.710 g peel, 0.025 g seed). Intriguingly, while peel inclusion enhanced total sugar content and antioxidant activity, seed incorporation exerted a contrasting effect by reducing total sugar content and limiting antioxidant activity.

Immature carob pods extract and its fractions prevent lipid metabolism disorders and lipoprotein-rich plasma oxidation in mice: A phytochemical and pharmacological study

ETHNOPHARMACOLOGICAL RELEVANCE

In Morocco carob fruits are used traditionally to treat hypercholesterolemia, diabetes and related diseases.

AIMS

This study was designed to evaluate the hypolipidemic activity of Ceratonia siliqua green pods extract and its fractions in Triton WR-1339 and high fat/cholesterol diet (HFCD) induced hyperlipidemia mice, as well as their ability to prevent lipoproteins oxidation in vitro.

MATERIALS AND METHODS

High performance liquid chromatography (HPLC) analysis was used to determine the phenolic composition of the immature carob pods extract (HWCE). Antioxidant activities were evaluated using the DPPH radical scavenging test as well as MDA measurement in oxidized lipoprotein rich plasma. Plasma lipids, glucose and biliary total cholesterol, as well as lipids level in liver and feces, were analyzed. The acute oral toxicity was performed in mice single dosed with the HWCE at 2000 and 5000 mg/kg body weight.

RESULTS

HPLC analysis shows that gallic acid is the main phenolic compound in the HWCE. The acute oral toxicity assessment revealed that the HWCE is not toxic (LD50 is greater than 5000 mg/kg body weight). In the acute hypolipidemic study, mice treated with the HWCE and its fractions exhibited a significant (P < 0.001) reduction in plasma total cholesterol (TC), triglycerides (TG) and low density lipoprotein-cholesterol (LDL-C) levels. Importantly, immature carob aqueous extract was more effective in lowering mice hypercholesterolemia than its fractions. Indeed, mice fed the HFCD for 12 weeks showed a significant raise in plasma TC, TG and LDL-C, as well as in hepatic and fecal TC and TG levels. The HWCE at 100 and 200 mg/kg body weight significantly (P < 0.001) reversed the plasmatic levels of these lipid parameters, increased plasma HDL-C level, reduced hepatic lipids accumulation, but increased cholesterol level in the bile and fecal lipids excretion. The HWCE decreased also the atherogenic index, the LDL-C/HDL-C ratio and plasma glucose level after 12 weeks' experiment. On the other hand, the HWCE was more effective in preventing mice lipoprotein-rich plasma oxidation than its fractions, with a concentration-dependent manner.

CONCLUSION

C. siliqua green fruits extract could be effective in preventing atherosclerosis and related cardiovascular complications through the inhibition of lipoprotein oxidation and cholesterol clearance.

Improving the physicochemical and antioxidative properties of fermented goat milk using carob molasses and some probiotic strains

Fermented goat milk samples, processed by adding 0, 2, and 4% carob molasses, and Bifidobacterium bifidum DSMZ or Lactobacillus helveticus CH5, were evaluated for their physicochemical, antioxidative, and sensory properties along with probiotic viability during storage. pH and viscosity gradually decreased over the storage period whereas their values increased with the increased amount of carob molasses. Bifidobacterium bifidum DSMZ or Lactobacillus helveticus CH5 kept higher viable numbers. Lactobacillus helveticus CH5 strain recorded higher viability. Increasing the added amount of carob molasses increased the total phenolic content, which in turn is reflected in the increase in antioxidant activity. Adding carob molasses participated in the partial masking of the goaty flavor and had no significant effect on the product's acceptability, which was strongly influenced by the progress of cold storage. Therefore, fermented goat milk described by its enhanced physicochemical and antioxidative properties could be obtained by adding carob molasses and probiotics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01382-2.

Biological Activities of Ceratonia siliqua Pod and Seed Extracts: A Comparative Analysis of Two Cretan Cultivars

Ceratonia siliqua L., commonly known as the carob tree, appears in most Mediterranean countries, often cultivated for the collection of its fruits to be used as food for humans and animals. This study was aimed at the phytochemical characterization of two common Cretan C. siliqua cultivars and the biological evaluation of deseeded pod and seed extracts regarding their putative use in cosmetics. Gas and liquid chromatographic techniques were used to assess their essential oil, fatty acid, and carbohydrate profiles. Cell-free assays, including free-radical scavenging; the inhibition of tyrosinase and collagenase; the blocking of advanced glycation end product (AGE) formation; along with assays in human skin fibroblast cultures, i.e., reactive oxygen species suppression, glutathione stimulation, and protection from oxidative stress and from ultraviolet (UVB) radiation, were also used. Extracts from both cultivars were found to possess antioxidant capacity, tyrosinase- and collagenase-inhibitory activities, an ability to block glucose-induced AGEs, and in certain cases, UVB absorbance and photoprotective activities. Seed extracts were in general more active, while the use of 30% aqueous methanol seemed to be more efficient than n-hexane for extraction. Serial partition of the most active extracts resulted in fractions with enriched biological activities. These properties make Cretan carob extracts and their fractions suitable candidates for use in cosmetics.

Nutritional, biochemical, and clinical applications of carob: A review

Carob is botanically called as Ceratonia siliqua and belongs to the Legumes family. The fruit is derived from hermaphrodite trees and hard in shape. The carob contains high sugar contents in pulp, fat in seed and minerals like potassium, calcium, and phosphorus are present in pods. Polyphenols and antioxidants are abundant in leaves and pods. It can be used for enhancing human health due to its high nutritional profile. Carob gum is used in the pharmaceutical industry in the form of pomades, anti-celiac ingredients, pills, and dental paste. The clinical carob can aid as an anti-cancer, anti-reflux, anti-diabetic, anti-diarrheal, anti-hyperlipidemia, anti-bacterial, anti-microbial, and anti-fungal. Nowadays, carob seeds are being used as an alternative to cocoa powder in food items whereas the leaves, pods, and seeds of carob are also historically used as food for animal feed. However, these parts of carob are available in markets with reasonable prices. Carob production, though with a rising contribution, contributes to the local economy. In this sense, we can incorporate knowledge on the chemical properties and the biological effect of carob fruits on human health. In this study, the supportive and health-promoting impacts of carob are discussed along with the clinical testing obtained from natural constituents of carob. In addition, further studies can be performed to extract and separate polyphenols and antioxidant potential for the development of functional that play a valuable role in pharmaceutical and food sectors.

Evaluation of Different Extraction Methods on the Phenolic Profile and the Antioxidant Potential of Ceratonia siliqua L. Pods Extracts

The present work was designed to investigate the effects of different extraction processes, namely ultrasonic-assisted, supercritical fluid, microwave-assisted and Soxhlet applied to carob pods. The total phenolic quantification and the antioxidant activity were assessed by the means of rapid in vitro spectrophotometric assays; the phenolic profile was identified using ultra-high performance liquid chromatography coupled to mass spectrometry. The results revealed that the phenolic compounds and the antioxidant capacity varied significantly with the nature of the extraction process. The content of total phenolic compounds ranged from 11.55 to 34.38 mg GAE/g DW; the content of total flavonoids varied from 3.50 to 10.53 mg QE/g DW, and the content of condensed tannins fluctuated from 3.30 to 6.55 mg CE/ g DW. All extracts performed differently on antioxidant activity when determined by the DPPH assay producing a dose-dependent response, with IC₅₀ extended from 11.33 to 6.07 µg/mL. HPLC analysis enabled the identification of nine compounds. As a function of the studied extraction methods, the phenolic compound contents were positively correlated with antioxidant activity.

Processing of Carob Kernels to Syrup by Ultrasound-Assisted Extraction

Carob syrup is one of the most important carob products, which can have applications in pastry and confectionery, as a fruit preservative, but also in the pharmaceutical field because of the antimicrobial activity due to its polyphenol content. Carob syrup is traditionally made through a very time-consuming process, involving solid–liquid extraction in boiling water and concentration at a high temperature (>100 °C), which potentially causes the degradation of the active compounds (i.e., procyanidins or flavonol glycosides). Therefore, in this work, an alternative and less drastic method based on ultrasound technology was proposed to produce carob syrup. Processing conditions (i.e., time, temperature, and liquid–solid ratio) influencing the extraction of total soluble solids (TSS) and total phenolic compounds (TPC) were optimized using a central composite design coupled to response surface methodology. Reliable mathematical models allowed us to predict the highest TSS (24 ± 2 °Brix) and TPC (1.7 ± 0.5 mg/mL) values that could be obtained at 15 min, 35 °C, and 2 mL/g. Finally, a different HPLC-DAD phenolic pattern was determined between syrups produced by traditional and ultrasound methods; epicatechin, 4-hydroxycoumaric acid, and ferulic acid were more concentrated in the former, while procyanidin B2, myricitrin, and quercitrin were prevalent in the latter one.

Ultrasound Assisted Extraction of Polyphenols from Ripe Carob Pods (Ceratonia siliqua L.): Combined Designs for Screening and Optimizing the Processing Parameters

Carob pulp has recently received great attention due to its considerable content of polyphenols having a wide range of health promoting effects. In this work, ultrasound assisted extraction was optimized sequentially using a screening Plackett–Burman design and non-standard central composite design coupled to response surface methodology and desirability function statistical tools, to find the best conditions for the extraction of nine polyphenols from carob pods. The gathered mathematical models showed that the highest significant factors influencing the extraction of all compounds were solid–solvent ratio, solvent concentration, and particle size, with the optimal results obtained at values of 0.2 g/mL, 40% ethanol, and 0.3 mm, respectively. Extraction temperature, time, sonication power, and frequency were set at 35 °C, 15 min, 100 W, and 37 kHz, respectively. These parameters help to reduce energy costs and to obtain the best possible extraction of polyphenols.

Continuous and pulsed ultrasound-assisted extraction of carob's antioxidants: Processing parameters optimization and identification of polyphenolic composition

Polyphenols in carobs have recently attracted great attention due to their wide range of biological and health promoting effects. A comprehensive study was conducted to find an optimum method for the extraction, purification and characterization of these valuable bioactive substances. Under this framework, the ultrasound-assisted extraction (UAE) of polyphenols from carob pulp was optimized by the maximization of the yield in total phenolics using response surface methodology. In particular, the effects of solid-solvent ratio, solvent concentration, extraction time, sonication amplitude, and sonication mode were investigated and optimized using a complete experimental design. In comparison to conventional extraction techniques, UAE offered a higher yield of antioxidants and a shorter processing time. Solid-phase extraction was evaluated as a clean-up strategy prior to the electrophoretic analysis of extracts. The results from the analysis of real samples revealed the predominance of gallic acid and highlighted the great influence of the ripening stage on carobs composition.

Combined use of β-cyclodextrin and ionic liquid as electrolyte additives in EKC for separation and determination of carob's phenolics-A study of the synergistic effect

In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of β-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM β-CD and 3 mM l-alanine tert butyl ester lactate (l-AlaC₄ Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 μg/g carob pulp) and unripe (205.10 μg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 μg/g unripe and ripe carob pulp).

Carob Pulp: A Nutritional and Functional By-Product Worldwide Spread in the Formulation of Different Food Products and Beverages. A Review

Carob (Ceratonia siliqua L.) pod is a characteristic fruit from the Mediterranean regions. It is composed by seeds, the valuable part due to the extraction of locust bean gum, and the pulp, considered a by-product of the fruit processing industry. Carob pulp is a mixture of macro- and micronutrients, such as carbohydrates, vitamins and minerals, and secondary metabolites with functional properties. In the last few years, numerous studies on the chemical and biological characteristics of the pulp have been performed to encourage its commercial use. Its potential applications as a nutraceutical ingredient in many recipes for food and beverage elaborations have been extensively evaluated. Another aspect highlighted in this work is the use of alternative processes or conditions to mitigate furanic production, recognized for its toxicity. Furthermore, carob pulp’s similar sensorial, chemical and biological properties to cocoa, the absence of the stimulating alkaloids theobromine and caffeine, as well as its low-fat content, make it a healthier potential substitute for cocoa. This paper reviews the nutritional and functional values of carob pulp-based products in order to provide information on the proclaimed health-promoting properties of this interesting by-product.

An in vitro study of the effect of carob (Ceratonia siliqua L.) leaf extracts on gilthead seabream (Sparus aurata L.) leucocyte activities. Antioxidant, cytotoxic and bactericidal properties

Carob leaves, the main residues of the carob tree, were investigated as a renewable and abundant source of bioactive compounds for fish aquaculture. Aqueous and ethanolic extracts obtained from carob leaves were characterized in terms of biochemical composition, antiradical and cytotoxic effects and immunostimulant and antibacterial activities. The ethanolic extract showed higher levels of total phenolics, flavonoids and condensed tannins and higher antioxidant activity than the aqueous extract. No significant immunostimulant effects were observed on gilthead seabream (Sparus aurata) head kidney leucocytes (viability, phagocytosis and respiratory burst activities and peroxidase content) after incubation for 24 h with different extracts. Furthermore, the ethanolic extracts used at 0.5, 0.75 and 1 mg mL^-1 and aqueous extracts at 1 g mL^-1 had a cytotoxic effect on PLHC-1 cells. When the bactericidal activity was tested against three fish pathogenic bacteria (Vibrio harveyi, Vibrio anguillarum and Photobacterium damselae) notable activity of the different extracts was detected against P. damselae at all three concentrations. A similar effect was demonstrated against V. haryeri when ethanolic extracts were used in the same range of concentrations. This work demonstrates interesting in vitro effects of carob leaf extracts and suggests it could be used as an alternative to chemical compounds with farmed fish. The concentration and nature of the extracts were very important in terms of any positive results.

Evolution of phytochemical and antioxidant activity of Tunisian carob (Ceratonia siliqua L.) pods during maturation

The Ceratonia siliqua fruits contain several substances known to have high adaptability to environmental conditions. The aim of this paper is to evaluate the changes in physicochemical properties of different Tunisian provenances of carob pulps harvested at three ripening stages. Furthermore, six provenances were investigated during the ripening process in terms of their moisture, ash, minerals, bioactive compounds, antiradical activity and sugar profile. The results demonstrated that all examined parameters are highly influenced by geographic origin. Concerning ripening impact, our data showed that water and ash content significantly decreased during the development of six provenances, as well as the bioactive and mineral contents. Thus, the total polyphenols (TP), total flavonoids (TF) and condensed tannins (CT) contents exhibited the highest levels in the unripe fruits. The antiradical activity trend was positively correlated to the behavior of the bioactive compounds content. Moreover, the sucrose, glucose and fructose were the main sugar qualified and quantified in carob pods at different ripening stages. At the maturity stage, the monosaccharide contents (glucose and fructose) were slightly reduced, while, the sucrose was rapidly accumulated. In conclusion, the ripening process diversely affected the nutritional composition and generally extended the exploitation of carob fruits. The study could provide valuable information about the suitability of carob pods at different maturity stages as potential biomaterials for nutraceutical applications.

Effect of adding carob molasses on physical and nutritional quality parameters of sesame paste

This study focused on the formulation of food products, based on sesame and carob. The possibility of developing blends from sesame paste and carob molasses, using molasses concentrations of 30, 40 and 50%, at 60, 70 and 80°Brix, respectively, has been studied. The blend prepared with 50% carob molasses at 60°Brix was found to be the most acceptable product, according to a sensory acceptability test. Sesame paste, supplemented with carob molasses, was evaluated for physical quality (oil separation, colour and texture) and nutritional composition (moisture, sugar, protein, fat, ash and polyphenols). Physical analysis showed that the addition of carob molasses to sesame paste improved its emulsion stability, changed its colour from beige to brown and modified its texture from fluid to solid. Nutritional analysis proved that mixing sesame paste with carob molasses provided a natural product, characterized by interesting nutritional value (protein: 16.97 g/100 g fry matter, fat: 12.05 g/100 g fry matter and sugar: 9.34 g/100 g fry matter), arising from the constituents of the two ingredients. Thus, the developed blend could offer a promising nutritious and healthy foodstuff to consumers.

A review of Tunisian medicinal plants with anticancer activity

Cancer is a major public health problem in the world. The use of the medicinal plants in cancer prevention and management is frequent in Africa, especially in Tunisia, and it is transmitted from generation to generation within cultures. Many previous studies showed that a wide range of Tunisian medicinal plants exerted cytotoxic and anticancer activity. A comprehensive review was conducted to collect information from scientific journal articles, including indigenous knowledge researches, about Tunisian medicinal plants used for the prevention and management of cancer. The aim of this review article is to provide the reader with information concerning the importance of Tunisian medicinal plants in the prevention and management of cancer and to open the door for the health professionals and scientists working in the field of pharmacology and therapeutics to produce new drug formulations to treat different types of cancer.

Valorization of carob waste: Definition of a second-generation bioethanol production process

The aim of this work was to develop a strategy for second-generation ethanol production from carob solid waste issued from Lebanese food industry. The pros and cons of submerged (SF) and solid-state fermentations (SSF) using S. cerevisiae on ethanol yield and productivity were compared, including the respective roles of upstream and downstream processes, such as the size reduction, or sugar and ethanol recovery processes. The design of experiments methodology was applied. Experimental results demonstrated that SSF applied to cut carob waste from carob syrup preparation was simpler to operate and more cost-effective, maintained yield and productivity (0.458g ethanol/g consumed sugar and 4.3g/(kg waste)/h) in comparison to SF (0.450g ethanol/g consumed sugar and 5.7g/(kg waste)/h), and was able to achieve ethanol production up to 155g/(kg waste) at low water demand, while SF reached only 78g/(kg waste) due to the limitations of the sugar extraction pretreatment.

Effect of borojo (Borojoa patinoi Cuatrecasas) three-phase composition and gum arabic on the glass transition temperature

BACKGROUND

The search for natural, novel, high-quality, stable food ingredients is an ongoing practice in the food industry. Pulp of borojo (Borojoa patinoi Cuatrecasas), which is a fruit of the Colombian Pacific region, can be separated into three phases: liquid (LP), medium (MP) and solid (SP) phases. The objective of this work was to evaluate the effect of the three-phase composition and gum arabic on their glass transitions temperatures (T(g)). The best mixture, LP-MP, MP-SP and LP-SP and gum arabic (GA) was identified by response surface methodology.

RESULTS

When adding GA to SP borojo phase in a 1:1 proportion, the resulting T(g) of the mixture was 132.27 °C whereas Tg for GA and SP-phase were 154.89 °C and 79.86 °C respectively, which supported this combination as attractive from a processing perspective and supports an industrial advantage of using borojo as food ingredient. Phases were characterized by high-performance liquid chromatography, Fourier transform infrared spectroscopy, confocal laser scanning microscopy and mass spectrometry. Low molecular weight compounds such as fructose for MP lowered T(g) whereas the presence of lignin increased T(g) of the mixtures as with the SP.

CONCLUSIONS

The addition of GA significantly increased T(g) of borojo phases so leading to propose them as novel food processing materials.