Compositional evaluation of selected agro-industrial wastes as valuable sources for the recovery of complex carbohydrates

Cocoa Bean Shell: A By-Product with High Potential for Nutritional and Biotechnological Applications

Cocoa bean shell (CBS) is one of the main solid wastes derived from the chocolate industry. This residual biomass could be an interesting source of nutrients and bioactive compounds due to its high content in dietary fibres, polyphenols and methylxanthines. Specifically, CBS can be employed as a raw material for the recovery of, for example, antioxidants, antivirals and/or antimicrobials. Additionally, it can be used as a substrate to obtain biofuels (bioethanol or biomethane), as an additive in food processing, as an adsorbent and, even, as a corrosion-inhibiting agent. Together with the research on obtaining and characterising different compounds of interest from CBS, some works have focused on the employment of novel sustainable extraction methods and others on the possible use of the whole CBS or some derived products. This review provides insight into the different alternatives of CBS valorisation, including the most recent innovations, trends and challenges for the biotechnological application of this interesting and underused by-product.

Pea (Pisum sativum L.) pod powder as a potential enhancer of probiotic Enterococcus faecium M74 in ice cream and its physicochemical, structural, and sensory effects

BACKGROUND

In this study, pea (Pisum sativum L.) pod powder (PPP) was incorporated (1% and 3% w/w) into a probiotic ice cream formulation containing Enterococcus faecium M74 to investigate the potential effect of PPP on the probiotic survivability in the ice cream throughout 60 days of frozen storage. Moreover, the produced symbiotic ice creams were evaluated for their physiochemical properties, stability, and sensory acceptability.

RESULTS

Incorporation of PPP into ice cream caused significantly (P < 0.05) increased protein and ash content and lower pH values. Besides that, the addition of PPP resulted in ice creams with higher hardness and lower overrun. A significant diminishing was observed in the melting rates of the ice creams as the percentage of PPP increased and storage time progressed. Ice cream with PPP presented lower lightness and higher greenness and yellowness compared with control. All ice creams had viable counts of E. faecium M74 of ≥6 log cfu g-1 during storage and provided the number of viable cells that the probiotic product should contain. On day 60, the viability of E. faecium M74 in ice cream containing 1% PPP (7.64 ± 0.02) was higher than the control (7.28 ± 0.00). Sensory analyses revealed that there was no statistical difference in ice cream with 1% PPP and the control without PPP in terms of general acceptability.

CONCLUSION

These results suggest that pea pods, which is a waste product of the pea industry and obtained at zero cost, could be used as a potential prebiotic and an agent to improve technological properties of dairy products. © 2022 Society of Chemical Industry.

Extraction and Characterization of Cocoa Bean Shell Cell Wall Polysaccharides

Cocoa bean shells (CBS), a by-product of the cocoa industry, from two cacao varieties and obtained after selected processing conditions (fermentation, drying, roasting) were characterized in terms of their chemical composition, where they were found to be a great source of carbohydrates, specifically dietary fiber, protein, ash, and polyphenols, namely quercetin, epicatechin, and catechin. Cell wall polysaccharides were isolated by alkaline extraction (0.5 M or 4 M KOH) and were found to be enriched primarily in pectic polysaccharides (80.6-86%) namely rhamnogalacturonan and arabinogalactan as well as hemi- cellulosic polysaccharides (13.9-19.4%). Overall, 0.5 M KOH polysaccharides were favored having provided a diverse profile of neutral sugars and uronic acids. When tested for the promotion of the growth of selected probiotic strains, CBS cell wall polysaccharides performed similarly or more than inulin and rhamnogalacturonan based on the prebiotic activity scores. The short-chain fatty acid profiles were characterized by high amounts of lactic acid, followed by acetic and propionic acid.

Partial Substitution of Corn Grain in the Diet with Beet Pulp Reveals Increased Ruminal Acetate Proportion and Circulating Insulin Levels in Korean Cattle Steers

We investigated the effects of the partial substitution of corn grain in the diet with beet pulp on growth performance, ruminal fermentation characteristics, microbial profiles, and blood lipogenic parameters in fattening steers. Twelve Korean cattle steers (body weight, 485 ± 19.32 kg; age, 18.0 ± 0.17 months) were equally divided into corn grain (CG) and beet pulp (BP) groups. Approximately 75% of dry matter of the requirement was offered as a concentrate portion, and the remaining 25% was offered as oat straw. Eighty percent of the concentrate portion was provided by a pelleted basal concentrate, and the remaining 20% with corn grain for the CG group, or 18% beet pulp plus 2.0% rumen-protected fat for the BP group, respectively, by top dressing. The experiment was conducted for 14 weeks, including a 2-week acclimation period. Growth rate was not affected by beet pulp feeding (p = 0.55). The molar proportions of ruminal acetate (p < 0.05) on wk 4, the relative abundances of ruminal cellulolytic bacteria, including Fibrobacter succinogenes (p = 0.01) and Ruminococcus albus (p = 0.04) on wk 12, and serum insulin concentrations (p < 0.05) on wk 12 were higher in the BP group than in the CG group, whereas the molar proportions of propionate (p < 0.05) on wks 8 and 12 and serum nonesterified fatty acids (p < 0.05) on wk 12 were lower in the BP group. Beet pulp could be used as a lipogenic energy source without affecting growth performance during the fattening period of cattle.

Cocoa bean shells: a review into the chemical profile, the bioactivity and the biotransformation to enhance their potential applications in foods

During processing, cocoa bean shells (CBS) are de-hulled from the bean and discarded as waste. Undermined by its chemical and bioactive composition, CBS is abundant in dietary fiber and phenolic compounds that may serve the valorization purpose of this by-product material into prebiotic and functional ingredients. In addition, the cell-wall components of CBS can be combined through enzymatic feruloylation to obtain feruloylated oligo- and polysaccharides (FOs), further enhancing the techno-functional properties. FOs have attracted scientific attention due to their prebiotic, antimicrobial, anti-inflammatory and antioxidant functions inherent to their structural features. This review covers the chemical and bioactive compositions of CBS as well as their modifications upon cocoa processing. Physical, chemical, and enzymatic approaches to extract and bio-transform bioactive components from the cell wall matrix of CBS were also discussed. Although nonspecific to CBS, studies were compiled to investigate efforts done to extract and produce feruloylated oligo- and polysaccharides from the cell wall materials.

Improvement of feed intake, digestibility, plasma metabolites, and lactation performance of dairy cows fed mixed silage of sugar beet pulp and rice straw inoculated with lactic acid bacteria

A study was conducted to investigate the inclusion effects of sugar beet pulp and rice straw mixture silage with inoculation (BRMS), in place of whole-plant corn silage (CS), on the dry matter intake, total-tract nutrient digestibility, plasma metabolites, rumen fermentation, and lactation performance in high-production dairy cows. Sixteen multiparous Holstein cows (body weight, 622 ± 35 kg; days in milk, 90 ± 11 d; mean ± standard deviation) were used in our experiments; the experiments were based on a repeated 4 × 4 Latin square design for 21 d, and each experimental period consisted of 14 d of adaptation, followed by 7 d of data collection. The 4 dietary treatments used were (dry matter basis): (1) 0% BRMS and 28.6% CS (0BRMS); (2) 4.3% BRMS and 24.3% CS (15BRMS); (3) 8.60% BRMS and 20.0% CS (30BRMS); and (4) 12.9% BRMS and 15.7% CS (45BRMS). The increasing inclusion of dietary BRMS was observed to linearly increase the total volatile fatty acids and the propionate concentration. The dry matter intake and digestibility values of neutral detergent fiber and acid detergent fiber increased linearly as the percentage of BRMS increased up to 45%. Milk yield linearly increased with the increase in the content of BRMS (39.0, 39.8, 40.9, and 40.3 kg/d for 0BRMS, 15BRMS, 30BRMS, and 45BRMS, respectively). The increasing inclusion of dietary BRMS induced a decrease in the ammonia nitrogen and milk urea nitrogen concentration, leading to a linear increase in milk protein production (1.15, 1.26, 1.35, and 1.27 kg/d for 0BRMS, 15BRMS, 30BRMS, and 45BRMS, respectively). In conclusion, the diets with the replacement of CS with BRMS up to 45% were beneficial to the production performance of high-production dairy cows, indicating that this method may be an appropriate use of sugar beet pulp and rice straw.

Valorisation of walnut shell and pea pod as novel sources for the production of xylooligosaccharides

According to the high interest in agro-industrial waste reutilisation, underutilised lignocellulosic materials, such as walnut shell (WS) and pea pod (PP), come in focus. The aim of this paper was to evaluate WS and PP as sources for the production of xylooligosaccharides (XOS). Hemicelluloses from WS and PP were recovered by combining varying parameters of delignification and alkaline extraction. At optimal recovery conditions, the fractions were further hydrolysed to XOS using GH11 endo-xylanase, by varying time and enzyme concentration. Xylose was predominant in the monomeric composition of the obtained hemicelluloses, building low-branched (arabino)glucuronoxylan, in WS exclusively, while in PP some xyloglucan as well. Delignification was essential for high recovery of total xylose from the materials, up to at least 70 %. High xylan conversions were obtained for 24 h hydrolysis, resulting in xylobiose and xylotriose when using low enzyme concentration, while in xylose and xylobiose with high enzyme concentration.

Waste streams in onion production: Bioactive compounds, quercetin and use of antimicrobial and antioxidative properties

Onion production generates abundant waste with high contents of bioactive compounds. These might have several beneficial functional properties for fortification of foods. To understand the variety and potential for further use, we examined various parts of the plants (edible/inedible waste/outer skin of onion), as well as extraction in water/ethanol and by shaking/sonication. Quercetin content and antioxidant capacity were initially determined for extracts of edible and waste parts of red, yellow and white onions, and red shallots. Ethanol extracts of the waste fraction had the highest quercetin content and antioxidant capacity. Except white onion, which contained no quercetin, the dried waste ethanol extracts contained up to 15 mg quercetin g^-1 and had an antioxidant capacity of nearly 40 mg Trolox equivalents g^-1. Furthermore, the dried skin ethanol extract of yellow onion, which is commercially the most available fraction, contained 8 mg quercetin g^-1, with antioxidant capacity of 25 mg Trolox equivalents g^-1 and high antimicrobial activity. Dried yellow onion skin showed good stability for the quercetin content under various storage conditions (4, 25, 37, 40 °C; dark/light; dry/moist air/in water). Bacteria, bacterial spores, yeast and mould counts remained unchanged for dried onion skin over 5 days under storage conditions that can promote food spoilage, indicating exceptional microbial stability. Finally, two different applications are demonstrated for dried yellow onion skin: tablets for home use (tablets as more convenient form of storage and for simple dosing in cooking), and a stabilisation additive (prolonged shelf-life of olive oil). Both represent efficient and straightforward approaches through waste prevention and food fortification.

Valorization of Banana and Red Beetroot Peels: Determination of Basic Macrocomponent Composition, Application of Novel Extraction Methodology and Assessment of Biological Activity In Vitro

The nutritional and bioactive content of banana and red beetroot peels was investigated. The basic macrocomponent composition was determined using standard AOAC (Association of Official Analytical Chemists) methods, while the recovery efficiency of bioactive compounds was investigated using conventional and innovative extraction techniques (subcritical water extraction, ultrasound- and microwave-assisted extraction). Extracts were analyzed for biological effects in vitro on human hepatic, tongue and colon cancer cell lines. A macrocomponent analysis revealed a notable amount of dietary fiber in banana and beetroot peels (39.0 and 33.6% dmb) and a relatively high content of protein in beetroot peel (18.3% dmb). Regarding the micronutrients-minerals, banana and beetroot peels were shown to be a very good source of potassium (75.06 and 41.86 mg g−1 dmb). Both extracts of banana and beetroot peels obtained by conventional extraction - decoction (100 °C, 20 min) exhibited the highest total phenolic content and antioxidant capacity. Additionally, in banana peel, these extracts were the richest in dopamine content (12.63 mg g−1 dmb). Extraction by infusion (80 °C, 30 min) yielded a beetroot peel extract with the highest total betacyanin content (9.80 mg g−1 dmb). Biological effects in vitro were dose- and time-dependent, as well as influenced by the presence of polysaccharides.

Difficulties with Use of Cocoa Bean Shell in Food Production and High Voltage Electrical Discharge as a Possible Solution

The cocoa and chocolate industries have huge problems with the utilization of waste generated during the production process. Waste material generated during production include cocoa pod husk, pulp, and cocoa bean shell. Cocoa shell is a by-product that has great potential because of its composition. It consists of dietary fibers, proteins, polyphenols, methylxanthines, etc. However, despite its favorable composition, cocoa shell often cannot be used directly in food production because it may contain components that are harmful for human health. Cocoa shell can carry mycotoxins, different microorganisms, polycyclic aromatic hydrocarbons, and heavy metals. High voltage electrical discharge presents a novel non-thermal method that has great potential for the decontamination of waste materials and can also be used for extraction of valuable compounds from cocoa shell.

Cocoa Bean Shell-A By-Product with Nutritional Properties and Biofunctional Potential

Cocoa bean shells (CBS) are one of the main by-products from the transformation of cocoa beans, representing 10%‒17% of the total cocoa bean weight. Hence, their disposal could lead to environmental and economic issues. As CBS could be a source of nutrients and interesting compounds, such as fiber (around 50% w/w), cocoa volatile compounds, proteins, minerals, vitamins, and a large spectrum of polyphenols, CBS may be a valuable ingredient/additive for innovative and functional foods. In fact, the valorization of food by-products within the frame of a circular economy is becoming crucial due to economic and environmental reasons. The aim of this review is to look over the chemical and nutritional composition of CBS and to revise the several uses that have been proposed in order to valorize this by-product for food, livestock feed, or industrial usages, but also for different medical applications. A special focus will be directed to studies that have reported the biofunctional potential of CBS for human health, such as antibacterial, antiviral, anticarcinogenic, antidiabetic, or neuroprotective activities, benefits for the cardiovascular system, or an anti-inflammatory capacity.

Graded replacement of corn grain with molassed sugar beet pulp modulates the fecal microbial community and hindgut fermentation profile in lactating dairy cows

High starch lactation diets not only enhance the risk of subacute ruminal acidosis but also of hindgut acidosis, which increases the risk of dysbiosis and the depression of fiber degradation. We recently showed that replacing corn with molassed sugar beet pulp (Bp) improved fiber degradation in high-producing dairy cattle, possibly because of an improvement of rumen and hindgut conditions for microbes by Bp feeding. However, little is known about the effects of high inclusion rates of Bp on hindgut microbes and fermentation. Thus fecal grab samples were taken from 18 high-yielding Simmental cows after 28 d of feeding 3 different levels of Bp (n = 6) for bacterial 16S rRNA amplicon sequencing. In addition, the reticular pH was continuously monitored with indwelling sensors and eating and ruminating behavior was evaluated with noseband sensors. The Bp inclusion rates were 0 g/kg (i.e., no Bp inclusion as control, CON), 120 g/kg (12Bp), or 240 g/kg (24Bp) replacing corn grain and limestone on a dry matter basis. The amount of time spent eating and ruminating was unaffected by Bp level, and the daily fluctuation in the reticular pH was reduced by 25% with Bp inclusion from 0.8 in the CON diet to 0.6 in 24Bp fed animals. Also, the fecal pH tended to increase with dietary Bp inclusion. Fecal acetate production showed a quadratic tendency with the lowest concentration (58.9%) of the total short-chain fatty acid in the 12Bp treatment. Inclusion of Bp up to 24% of the diet decreased the fecal butyrate proportion by 27%. The Shannon diversity index was increased from 5.50 to 8.09 with dietary Bp inclusion indicating increased species diversity. Of the 200 most abundant operational taxonomic units, 25 were increased by dietary Bp inclusion, whereas 15 were decreased and 7 were quadratically affected. The second most abundant group was proposed taxon "CF231" of the family Paraprevotellaceae. Although it accounted for only 2.52% of the operational taxonomic units in the CON diet, it was increased by 64% with dietary Bp inclusion. The largest relative change in the abundance was found for the genus Fibrobacter that increased more than 14-fold from 0.04% (CON) to 0.66% (24Bp). In conclusion, feeding molassed sugar beet pulp as partial substitution of corn up to 240 g/kg is a viable alternative that promotes ruminal and hindgut fermentation by supporting physiological pH and bacterial diversity.

Cocoa bean shell waste valorisation; extraction from lab to pilot-scale cavitational reactors

The use of zero-waste processes to integrate food-waste valorisation into the circular economy equation is currently one of the hottest topics in sustainability research. This goal is still far from being fully achieved despite the release of a number of patents and papers that deal with the topic. The present work aims to valorise cocoa shells, one of the main by-product of the roasting process, in order to enhance the effective extraction of high added value compounds by means of green protocols. The high potential added value of the residual waste has been demonstrated via a direct analytical comparison of extracts and bean composition. A range of raw matrix extraction procedures have been investigated in order to define the best solvent and technology; ultrasound (US) and hydrodynamic cavitation (HC) were compared with conventional methods. The high-energy microenvironments generated by cavitation substantially promote fast biomass deconstruction with low energy consumption. The optimized protocol couples a HC reactor with a ternary water/ethanol/hexane mixture, simultaneously providing a hydrophilic product, which is rich in methylxanthines and polyphenols, and a lipid layer. Sequential milling and sieving pretreatment provided an enriched shell fraction via the partial removal of husk fibres (54.45 vs. 81.36 w/w % total fibres). The disposal of the latter reduces mass balance, but is rerouted into animal feedstock components and crop mulching. The protocols herein reported produce valuable extracts, which are rich in antioxidant flavanols (catechins and epicatechins), theobromine (32.7 ± 0.12 mg/g shells), caffeine (1.76 ± 0.08 mg/g shells) and cocoa butter, in a simple and easy manner. This new valorisation process afforded 20.5 w/w % and 15.8 w/w % hydrophilic and lipophilic fractions, respectively, when scaled up to function in a pilot flow reactor. The fatty acids, obtained in remarkable yield (forming the 96.4 w/w % of the total light part) well match the commercial cocoa butter profile. The antioxidant extract shows an impressive total phenolic content of 197.4 mg/g extract (gallic acid eq.), with a radical scavenging activity of 62.0 ± 3.1 μg/mL (expressed in DPPH EC₅₀). This work should facilitate industrial design for the convenient recovery of cocoa by-products as part of a zero-waste strategy.

Pea soluble polysaccharides obtained from two enzyme-assisted extraction methods and their application as acidified milk drinks stabilizers

The objective of this work was characterize and evaluate the protein-stabilizing property of pea soluble polysaccharide (PSPS) extracted from pea by-products using spray-drying and ethanol precipitation oven drying, obtaining PSPS-A and PSPS-B, respectively. The weight average molecular weight (Mw) of PSPS-A and PSPS-B were 625 kDa and 809 kDa, respectively. The results of Fourier transform infrared spectroscopy (FT-IR) analysis indicated that PSPS-A, PSPS-B and soybean soluble polysaccharide (SSPS) contained the same functional groups. The absolute negative charges of PSPS-A or PSPS-B in aqueous solution were slightly higher than that of SSPS at pH 2.0 to 7.0. The apparent diameter of PSPS-B (479.1 nm) was larger than that of PSPS-A (127.7 nm) and SSPS (209.5 nm) were measured by dynamic light scattering. The AFM images revealed that both PSPS-A and PSPS-B possessed star-like structures with more side chains as compared to SSPS. It was found that the addition of 0.15% PSPS-A or 0.1% PSPS-B was adequate to prevent the aggregation of protein and obtain stable dispersion. Furthermore, PSPS has a wider pH range (pH 3.6-4.6) to stabilize milk protein than SSPS (pH 3.6-4.2).

Graded replacement of maize grain with molassed sugar beet pulp modulated ruminal microbial community and fermentation profile in vitro

BACKGROUND

Molassed sugar beet pulp (Bp) is a viable alternative to grains in cattle nutrition for reducing human edible energy input. Yet little is known about the effects of high inclusion rates of Bp on rumen microbiota. This study used an in vitro approach and the quantitative polymerase chain reaction technique to establish the effects of a graded replacement of maize grain (MG) by Bp on the ruminal microbial community, fermentation profile and nutrient degradation.

RESULTS

Six different amounts of Bp (0-400 g kg^-1 ), which replaced MG in the diet, were tested using the in vitro semi-continuous rumen simulation technique. The increased inclusion of Bp resulted in greater dietary content and degradation of neutral detergent fibre (P < 0.01). Further, Bp feeding enhanced (P < 0.01) the abundance of genus Prevotella and shifted (P < 0.01) the short-chain fatty acid patterns in favour of acetate and propionate and at the expense of butyrate. A total replacement of MG with Bp resulted in an increased daily methane production (P < 0.01).

CONCLUSION

Results suggest positive effects of the replacement of MG by Bp especially in terms of stimulating ruminal acetate and propionate fermentation. However, high replacement rates of Bp resulted in lowered utilization of ammonia and higher ruminal methane production. © 2017 Society of Chemical Industry.