Novel Prediction of Total Fat Content in Cocoa Beans by FT-NIR Spectroscopy Based on Effective Spectral Selection Multivariate Regression

Total fat content is a major quality parameter that chocolate manufactures consider when selecting cocoa beans. This paper attempted the feasibility of measuring total fat content in cocoa beans by using Fourier transform near-infrared (FT-NIR) spectroscopy based on a novel systematic study on efficient spectral variables selection multivariate regression. After the efficient spectra interval selection by synergy interval partial least squares (Si-PLS), the data were treated with support vector machine regression (SVMR) leading to synergy interval support vector machine regression (Si-SVMR). Experimental results showed that the model based on the novel Si-SVMR algorithm was superior to the others. The optimum results were assessed by root-mean-square error of prediction (RMSEP) and correlation coefficient (R _pre) in the prediction set. The performance of Si-SVMR model was RMSEP?=?0.015 and R _pre?=?0.9708. This study has demonstrated that the total fat content in cocoa beans could rapidly be predicted by FT-NIR spectroscopy and Si-SVMR technique. The novel strength and accuracy of Si-SVMR in contrast to other multivariate algorithms has been derived.     

Tocopherols in cocoa butter obtained from cocoa bean roasted in different forms and under various process parameters

Obtaining good quality chocolate strongly depends on raw material, i.e. cocoa beans. The processing of cocoa beans consists of some important steps, including fermentation, drying fermented beans and roasting. Traditionally roasting is performed on whole beans but currently, roasting crushed cocoa beans or cocoa liquor becomes more and more popular. Many biologically active compounds may be found in the cocoa beans, including tocopherols. This work investigates the influence of the constant or variable roasting process parameters (temperature, velocity and relative humidity of roasting air) on the tocopherol concentration in cocoa butter (CB) extracted from cocoa beans originating from Togo and roasted in two different forms, namely as whole and crushed beans. Whole cocoa beans were roasted to a 2% moisture content and crushed cocoa beans were firstly partially dried which further enables easier dehusking, then ground, dehusked and roasted until their humidity decreased to around 2%. Roasting resulted in lowering the content of individual tocopherols in analyzed material. The degree of degradation of tocopherols in CBs was different, depending on the form of roasted beans from which these CBs were extracted. Higher concentrations were determined in CBs extracted from beans roasted in the form of crushed samples comparing to CBs obtained from beans roasted as a whole. The study investigates different roasting parameters of crushed beans, none of which drastically lowered the concentration of tocopherols in extracted CBs. Their concentration in CBs extracted from whole beans was, on the other hand, influenced by roasting air parameters. In case of whole beans roasted under constant parameters, application of 150 °C proved to be more favorable than roasting at 135 °C, as well as application of “dry” air and 1 m/s roasting air velocity. Discussing the variable roasting process parameters, in case of applied roasting temperature it is more favorable to change it from 150 °C to 135 °C, than the other way round. Changing the relative humidity of roasting air from 5 to 0.3%, lower degradation of tocopherols in CB occurs when the process is conducted at 150 °C. It may be further concluded that a direct dependence between the velocity of roasting air varied during the process and the concentration of tocopherols in extracted CB may not be indicated. In conclusion, it is stated that the temperature of the air applied during the roasting process has the decisive influence on the tocopherol content in CBs extracted from cocoa beans subjected to the process.     

Antioxidant capacity of cocoa beans and chocolate assessed by FTIR

The total antioxidant capacity (TAC) and total phenolic compounds (TPC) of cocoa beans and chocolate produced from spontaneous and inoculated fermentations of different cocoa varieties were evaluated. Fourier transform infrared spectroscopy (FTIR), as well as conventional methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), was used to determine TAC and TPC. Chocolate showed higher (p < 0.05) TPC (47.17–57.16 mg GAE/g) and TAC (1.66–2.33 mM TE/g and 8.86–11.35 mM TE/g as measured by DPPH and ABTS, respectively) than cocoa beans (6.30–26.05 mg GAE/g, 0.24–1.17 mM TE/g and 1.29–4.83 mM TE/g for TPC, DPPH and ABTS, respectively). Partial least square (PLS) model for infrared data showed a good calibration coefficient (R²cal > 0.94), indicating that the FTIR technique represents a fast and reliable tool to evaluate TPC and TAC in cocoa beans and chocolate.     

Influence of roasting conditions on fatty acid composition and oxidative changes of cocoa butter extracted from cocoa bean of Forastero variety cultivated in Togo

Cocoa butter is responsible for physico-chemical, rheological and sensory properties of chocolates. Forastero cocoa beans are rich in cocoa butter. Roasting of cocoa beans is an essential step of their processing, giving rise to many desirable transformations. On the other hand, it causes changes in certain valuable ingredients including also cocoa butter. This article studies the influence of roasting conditions, i.e. temperature, humidity and flow velocity of roasting air, on the fatty acid composition, peroxide value and content of conjugated dienes and trienes in cocoa butter extracted from cocoa beans. Generally, in most cases roasting did not increase the peroxide value. In the constant conditions due to obtained results of PV, CD and CT values it is recommended to roast cocoa beans at the temperature of 150 °C, 1 m/s air velocity and 5% relative humidity. In the variable conditions lower values of PV, CD and CT were achieved when cocoa beans were roasted in variants with changing temperature from 150 °C to 135 °C or with changing air velocity from 1 to 0.5 m/s. Generally, the roasting process substantially did not change the content of each fatty acid, regardless of the applied conditions.     

Effect of Fermentation Time on the Phenolic,Flavonoid and Vitamin C Contents and Antioxidant Activities of Okra (Abelmoschus esculentus) Seeds

The objective of this study was to evaluate the effect of fermentation on the phenolic, vitamin C and total flavonoid contents and antioxidant properties of okra seed. The okra seeds were removed from the pod of matured and fibrous okra that cannot be easily cut with kitchen knife, and was allowed to undergo chance fermentation for 120 h. Samples were taken for antioxidant analysis at 24 h, 72 h and 120 h, respectively. The aqueous extracts of fermented and unfermented okra seeds were obtained and subsequently used for the analysis. The phenolic, vitamin C and total flavonoid contents and the antioxidant properties (ferric reducing antioxidant power (FRAP) and 1, 1-diphenyl-2 picrylhydrazyl (DPPH) free radical-scavenging ability) of the extracts were determined. The results revealed that fermented okra seeds had significantly (p < 0.05) higher phenolic content, vitamin C, total flavonoid and non-flavonoid contents and showed greater antioxidant activities than unfermented okra seed. Okra seeds fermented for 24 h exhibited the highest ferric reducing antioxidant power of 980 mgAAE/100 g and the least IC₅₀ of 2.27 mg/ ml for DPPH free radical-scavenging ability than the others. Okra seeds fermented for 24 hours had significantly (p < 0.05) higher antioxidant activities. The product from fermented okra seeds could be used for the production of functional foods.     

Effects of incubation and polyphenol oxidase enrichment on colour, fermentation index, procyanidins and astringency of unfermented and partly fermented cocoa beans

Incubation of unfermented and partly fermented cocoa beans in acetate buffer, pH 5.5, at 45 °C increased yellowness, total colour differences and fermentation index value of the cocoa bean powders and decreased cocoa procyanidins (monomers to pentamers), and their astringency. Fermentation index and (–)‐epicatechin content, equivalent to those of fully fermented beans, were reached by unfermented beans after 4–8‐h incubation, but not by partly fermented beans even after 16 h. During incubation of partly fermented cocoa beans enriched with polyphenol oxidase, yellowness and fermentation index value were increased, whilst (–)‐epicatechin was decreased. Tyrosinase had a less significant effect in yellow colour formation, but showed a significant reduction of (–)‐epicatechin and increase in fermentation index compared with crude cocoa polyphenol oxidase. However, both enzymes have similar effects on procyanidin degradation and astringent taste reduction. Incubation of cocoa beans for 16 h increased the cut test score of unfermented and partly fermented beans by 50 and 30%, respectively.     

Activation of remaining key enzymes in dried under-fermented cocoa beans and its effect on aroma precursor formation

Incubation-activation of remaining key enzymes in dried under-fermented cocoa beans and its effect on aroma precursor formation has been studied using defatted unfermented and partly fermented cocoa bean powders. Results of the study showed that aspartic endoprotease, carboxypeptidase and invertase were significantly inactivated during fermentation and drying, and the effect of fermentation was significantly lower than that of drying. The enzyme activities remaining in these beans were still sufficient to carry out enzymatic reaction during incubation. Peptide patterns, resulting from incubation of unfermented and partly fermented beans powders, were quite similar to the well-fermented patterns. Meanwhile, free amino acid concentrations of the unfermented beans were significantly increased during the first 4 h of incubation and then remained constant; however, with partly fermented beans, the formation continued and the hydrophobic and total free amino acid concentrations reached the value of well-fermented beans after 24 h of incubation. Reducing sugar concentrations of both unfermented and partly fermented cocoa beans could reach the level of well-fermented beans by incubation.     

Antioxidant and biological activity of phenolic pigments from Theobroma cacao hulls extracted with supercritical CO2

Theobroma cacao L. (Sterculiaceae) and cocoa-derived products are phenolics-rich food; these products are largely studied because of the antioxidant and antiradical in vitro properties of phenolic constituents. Cocoa hulls are the principal by-product of cocoa, separated from the cotyledons during the pre-roasting process or after the roasting process of T. cacao beans (de-hulling/de-husking step). This by-product is a matrix rich in fiber (namely insoluble, but also represented by pectins) and phenolics. Supercritical CO₂ is a powerful mild technology able to extract and fractionate from plant or animal foods without the use of organic solvent. This approach was used to extract some phenolics fractions from cocoa hulls. Only two recovered fractions, (150 bar, 50 °C, re-dissolved in acetone; 200 bar, 50 °C, re-dissolved in acetone), apparently free from (-)epicatechin, catechin and phenolic acids, showed protective action in an in vitro test (SH-SY5Y cells, differentiated to a neuronal phenotype using retinoic acid and then exposed to ischemic damage), similar to the action of cabergoline and vitamin E. We suggest the use of supercritical CO₂ for the isolation of bioactive fractions from cocoa hulls and an in vitro model as a useful model to study the antioxidant/antiradical properties of isolated phenolic pigments.     

Purification and characterization of angiotensin I-converting enzyme inhibitory peptides of small red bean (Phaseolus vulgaris) hydrolysates

Angiotensin I-converting enzyme (ACE) inhibitory activity was investigated for small red bean (Phaseolus vulgaris) protein hydrolysate produced by sequential digestion of Alcalase, papain followed by in vitro gastrointestinal simulation. The hydrolysate had ACE inhibitory activity with IC₅₀ of 67.2 ± 1.8 μg protein/mL. Peptides responsible for potent ACE inhibitory activity were isolated by a three-step purification process, including ultrafiltration, gel filtration and preparative reverse phase high performance chromatography (RP-HPLC). The fraction obtained after RP-HPLC fractionation with the highest activity yielded an IC₅₀ of 19.3 ± 1.4 μg protein/mL. Enzymatic kinetic studies using this fraction demonstrated competitive inhibition with K_i of 11.6 ± 1.7 μg protein/mL. Mass spectrometric characterization identified for the first time the octapeptide PVNNPQIH which demonstrated an IC₅₀ value of 206.7 ± 3.9 μM. The results expand the knowledge base of ACE inhibitory properties of small red bean protein hydrolysate and should be useful in further identification of specific ACE inhibitory peptides in beans.     

Effect of moisture on salmonella spp. heat resistance in cocoa and hazelnut shells

The heat resistance of food-poisoning outbreak and non-outbreak associated strains of Salmonella (S. Enteritidis, S. Montevideo, S. Napoli, S. Oranienburg, S. Poona, S. Senftenberg and S. Typhimurium) was established in confectionery-related materials such as crushed cocoa bean and hazelnut shells at low moisture contents (≤ 4% w/w). The two most heat resistant strains in cocoa and hazelnut shells at ca. 4% w/w moisture were S. Oranienburg and S. Enteritidis PT30. Both strains were associated with outbreaks from dried materials. Their D_100°C values were ca. 2.5 min in crushed cocoa bean shells and 7–11 min in crushed hazelnut shells. Addition of moisture to ca. 7% w/w markedly reduced D-values (D_80°C of 2–4.5 min) for both strains in the two matrices.     

Biotechnological process for producing black bean slurry without stachyose

Beans are important sources of proteins and other nutrients. However, stachyose and other oligosaccharides (RFOs) are present in this legume causing flatulence (H₂, CO₂ and CH₄), abdominal pain, and diarrhea. The problematic digestibility of these sugars in the small intestine is attributed to a lack of α-galactosidase, which is essential for the hydrolysis of α-1,6 linkages. The aim of the present work was to reduce the stachyose of black bean slurry by lactic acid fermentation using a selected Lactobacillus LPB56, an α-galactosidase producer. The bean slurry (6L) was fermented in a bioreactor with 1.3% (w/v) of CaCO₃, at 37 °C and 160 rpm. Bacterial cells increased from 2.4 × 10⁷ to 7.0 × 10⁸ CFU/mL, and the stachyose and other sugars were totally consumed after 18 h of fermentation. The maximum activity of α-galactosidase was 0.162 U/mL after 6 h. The fermentative process did not cause significant changes on the composition of the bean product.     

Extraction,identification and semi-quantification of oligopeptides in cocoa beans

Peptides and amino acids generated during cocoa bean fermentation are known to be the most important precursors for the development of cocoa aroma. Although cocoa fermentation and aroma development have been extensively studied, the cocoa oligopeptide fraction is under-investigated. In particular, the identification of specific peptide sequences and the quantification of cocoa peptides are scarce in the literature. The aim of this study was to investigate the presence of oligopeptides in fermented cocoa beans. Peptides were analysed by reversed phase LC/ESI-MS and LC/ESI-MS/MS, and the molecular masses of 44 different peptides were obtained by analysing the mass spectra associated with the most intense chromatographic peaks. Peptides were identified based on the exact molecular masses, mass fragmentation patterns and by comparison with vicilin and 21 kDa cocoa seed protein sequences. Semi-quantitative data on peptide presence in fermented cocoa samples of different geographic origin, different fermentation levels and on roasted products were also provided.     

Zinc bioavailability in different beans as affected by cultivar type and cooking conditions

Zinc bioavailability was studied in five cultivars of beans (Phaseolus vulgaris, L): white (Ouro Branco), black (Diamante Negro), and brown (BRS Radiante, Pérola and Talismã) cooked with or without soaking water. The cooked bean flours or ZnCO₃ were added to the test or control diets to provide 15 mg Zn/kg diet and were fed to weaning Wistar male rats for 42 days. Blood and femur were collected for analyses of plasma and erythrocyte Zn, bone weight and bone/dietary mineral ratio. Zinc bioavailability of Ouro Branco bean cooked with soaking water was higher than the other cultivars and similar to the control diet. Talismã without soaking water showed the lowest values for most of the parameters analyzed. Zinc bioavailability was not affected neither by the cooking process itself nor by the contents of phytate, tannins and dietary fiber, but it varied according to the bean cultivar and the phytate × calcium:zinc molar ratio.     

Influence of daily consumption of synbiotic soy-based product supplemented with okara soybean by-product on risk factors for cardiovascular diseases

This study aimed to investigate the effect of a synbiotic fermented soy product supplemented with okara (a by-product from soybean) on cardiovascular disease risk markers in healthy men. In a randomized, double-blinded, placebo controlled trial, thirty-six normocholesterolemic men were assigned to two groups. Subjects consumed daily 100 g of soy-based product fermented with Lactobacillus acidophilus La-5, Bifidobacterium animalis subsp. lactis Bb-12, and Streptococcus thermophilus (starter culture) (synbiotic group — S) (n = 18) or 100 g of unfermented soy-based product (placebo group — P) (n = 18) for 8 weeks. Fasting blood samples and anthropometric measurements were collected at the baseline (T₀), the end of week 4 (T₄), and the end of week 8 (T₈). Serum lipids, C-reactive protein, fibrinogen, and electronegative LDL were also analysed on T₀, T₄, and T₈. During the period of daily soy-based product consumption (from T₀ to T₈) the LDL-C mean decreased significantly (p < 0.05) in group S, resulting in a significant (p < 0.05) improvement of the LDL-C/HDL-C ratio. Comparing mean differences (T₈–T₀) between the two groups, the trend of LDL-C and LDL-C/HDL-C ratio reductions was higher in group S (14.1 mg/dL and 0.38 mg/dL, respectively) than group P (4.9 mg/dL and 0.17 mg/dL, respectively) (p > 0.05). Our results suggest limited lipid-lowering effects of synbiotic soy-based product supplemented with okara on cardiovascular risk markers in normocholesterolemic men.     

Comparison of polyphenol,methylxanthines and antioxidant activity in Theobroma cacao beans from different cocoa-growing areas in Colombia

The aims of the current work were to study the influence of geographical areas on polyphenol and methylxanthine contents and the antioxidant activity in cocoa beans from different cocoa-growing areas of Colombia, and to evaluate the possibility of establishing a classification based on the geographical areas of the cocoa-growing regions. Eighteen cocoa farms located in eleven cocoa-growing areas were analyzed. The statistical analysis showed significant differences (p < 0.05) in total polyphenol content (TPC), flavan-3-ol, epicatechin, catechin, caffeine and theobromine contents as well as the theobromine/caffeine ratio and the antioxidant capacity between some of the different sampled farms, showing a significant effect of the cocoa-producing region on these parameters. Generally, a proportional relationship has been proposed to exist between the polyphenol content with changes in altitude of plant crops, despite this, our results suggest that the lower the altitude, the more polyphenols, flavan-3-ols and epicatechin are produced by the cocoa plant. Results of the principal component analysis (PCA) indicate that caffeine content and the theobromine/caffeine ratio could serve as parameters to establish a cocoa bean classification according to the geographical area of the cocoa-growing regions.     

Cocoa brew inhibits in vitro α-glucosidase activity: The role of polyphenols and high molecular weight compounds

Cocoa brew showed a dose-dependent inhibitory activity against α-glucosidase (IC₅₀ 7.87 mg/mL). The cocoa brew was fractionated by ultrafiltration in a low molecular weight fraction (LMW < 10 kDa) and two melanoidin-rich fractions called high molecular weight (HMW > 30 kDa) and intermediate molecular weight (IMW 10–30 kDa) fractions. All fractions tested caused some inhibition with IMW that was the most active (IC₅₀ 2.37 mg/mL). LMW fraction was separated with Sephadex LH-20 in an unbound (containing monomeric and dimeric catechins) and a bound fraction. All the inhibitory activity was recovered in the unbound fraction. All the phenolic compounds identified with HPLC showed α-glucosidase inhibitory activity. IMW and HMW fractions were fractionated by ethanol precipitation. The fractions from IMW precipitated with 75 and 25% ethanol were found to contain power inhibitors of α-glucosidase activity (IC₅₀ 0.87 and 1.01 mg/mL, respectively). In the HMW sample, the fractions precipitated with 50 and 75% ethanol were found to be active against α-glucosidase activity. Most of the inhibitory activity against α-glucosidase of cocoa brew was due to the LMW fraction (56%) whereas IMW and HMW contributed for about 47% of the inhibitory activity. This study suggests that different components of cocoa may influence α-glucosidase activity.     

Composition of marama bean protein

The protein composition of marama beans, an indigenous African oilseed legume, was determined in comparison with soya beans. Marama bean protein contained a substantial amount of tyrosine compared with soya bean protein. It was slightly richer in proline than was soya. By SDS–PAGE, marama protein contained fewer protein bands than did soya. The patterns of these bands in marama under non-reducing and reducing conditions were similar, suggesting an absence of disulphide bonds. The vicilin (7S) and acidic 11S subunits seemed to be absent in marama. This is most unusual in legume proteins. Only a major basic legumin (11S) (20 kDa), medium (63 kDa) and high (148 kDa) molecular weight protein bands were separated for marama. Most polypeptides in the marama proteome map are basic compared with soya. Only one polypeptide match, comparable to soya, was tentatively identified. Marama protein composition is very different from that of soya.     

Effect of processing conditions on quality of green beans subjected to reciprocating agitation thermal processing

The effect of reciprocating agitation thermal processing (RA-TP) on quality of canned beans was evaluated in a lab-scale reciprocating retort. Green beans were selected due to their soft texture and sensitive color. Green beans (2.5 cm length × 0.8 cm diameter) were filled into 307 × 409 cans with carboxylmethylcellulose (0–2%) solutions and processed at different temperatures (110–130 °C) and reciprocation frequency (1–3 Hz) for predetermined heating times to achieve a process lethality (F_o) of 10 min. Products processed at higher temperatures and higher reciprocation frequencies resulted in better retention of chlorophyll and antioxidant activity. However, high reciprocation frequency also resulted in texture losses, with higher breakage of beans, increased turbidity and higher leaching. There was total loss of product quality at the highest agitation speed, especially with low viscosity covering solutions. Results suggest that reciprocating agitation frequency needs to be adequately moderated to get the best quality. For getting best quality, particularly for canned liquid particulate foods with soft particulates and those susceptible to high impact agitation, a gentle reciprocating motion (~ 1 Hz) would be a good compromise.     

Influence of preprocessing methods and fermentation of adzuki beans on γ-aminobutyric acid (GABA) accumulation by lactic acid bacteria

The effects of pre-processes (immersing, germinating, and cold shock) and fermentation conditions of adzuki beans on γ-aminobutyric acid (GABA) accumulation using mixed cultures of Lactococcus lactis and Lactobacillus rhamnosus were investigated in this study. Among the preprocessing methods, cold shock treatment resulted in the highest observed GABA content (201.2 mg/100 g); a 150-fold increase compared to the non-treated adzuki beans. The LAB strains grew rapidly in cold-treated adzuki bean substrates and reached 10⁸ cfu/ml after 24 h of fermentation at 30 °C. After optimization, the GABA yield reached 68.2 mg/100 ml; a 20-fold increase compared to the non-fermentation yield. The viable cell counts of LAB remained above 10⁸ cfu/ml after 28 days of storage at 4 °C. Our results suggest that the combination of cold shock pretreatment and fermentation by LAB may be used for the preparation of adzuki beans with high GABA content, which can then be used as a natural resource of functional foods.     

Effect of Fermentation Methods on Chemical and Microbial Properties of Mung Bean (Vigna radiata) Flour

Mung flours were fermented using spontaneous and backslopping methods for 72 h and microbial analysis over a period of 72 h fermentation was carried out. The samples were subjected to biochemical test, anti-nutrient and selected mineral and vitamin contents evaluation using standard methods. There was a gradual decline in pH from an initial value of 6.24 in unfermented flour to a pH of 3.68 in spontaneous fermentation and 3.87 in backslopping fermentation after 72 h. The total titratable acidity increased from 0.0085% to 0.0105% in fermented sample. The level of the increase did not differ significantly (p > 0.05) for the methods. Flours from back-slopping fermentation showed higher increase in protein and ash (17.59% and 18.25% respectively) than spontaneous fermentation with 16.70 % and 6.35% respectively. Similar increases were observed for calcium and iron. The decrease in zinc content was higher in spontaneous fermentation method than in back-slopping methods. Back-slopping fermentation sample had higher Vitamin A, lower phytate and tannin contents than spontaneous fermented sample. Samples from spontaneous fermentation showed significantly (p < 0.05) higher increases in microbial load (1.27 × 10⁵ − 4.08 × 10⁵ CFU/ml) than that from the back-slopping fermentation method (0.4 × 10⁵ − 2.9 × 10⁵ CFU /ml) within the same time interval. Back-slopping method improves the nutritional properties than spontaneous methods and could be encouraged at community levels.