Sweet Potato Peel Research Articles

Development of high fiber rich antioxidant biscuits from purple and orange sweet potato peels

Sweet potato peel (SPP), which consist of various natural bioactive compounds, could play an important role in ameliorating chronic diseases such as cancer, cardiovascular diseases, and other degenerative diseases and yet remained underutilized. The current study investigated the effect of orange or purple SPP powder at different level of substitution (2, 5, 10%) in the production of biscuits on the proximate, antioxidant potentials and consumer acceptance. Dietary fibre increased significantly (P < 0.05) with an increase in SPP powder, ranging from 2 to 2.3 g/100 g. The total phenolic content of the biscuits was between 101.21 and 147.7 GAE/mL, total flavonoid ranged from 22.7 to 42.2 RU/mL, ABTS radical content ranged from 2.7 to 42.2 (µg ascorbic/mL). Acceptable biscuits were obtained by incorporating 2% SPP powder. Thus, SPP powder could be used as a functional and nutraceutical ingredient in biscuit production.

Utilization Pemanfaatan Ekstrak Kulit Ubi Jalar Ungu Sebagai Pengganti Crystal Violet pada Pewarnaan Gram

Purple sweet potato has the high anthocyanin content. The anthocyanin content in purple sweet potato skin is higher than the anthocyanin in the tubers, namely 52.84-729.74 mg/100g while the tubers are 110.51 mg/100g. Natural dyes that have the potential to be extracted include anthocyanins. This research aimed to test anthocyanin dyes in purple sweet potato peel extract as the substitute for crystal violet in gram staining. The type of research used Quasi Experiments. This research was conducted in the Microbiology Laboratory of the Hasanuddin University Medical Faculty. In this research, extraction was carried out by using the solvent of Ethanol : Acetic Acid : Water (25: 1: 5). Furthermore, gram staining was carried out by using purple sweet potato peel extract using a concentration of 60%, 70%, 80%, 90%, 100% and crystal violet as positive control. The results of this research indicate that the staining used purple sweet potato peel extract concentrations of 60%, 70%, 80%, 90% in gram-positive Staphylococcus bacteria isolates showed poor bacterial staining results because the bacteria were not purple when compared to crystal violet dye. Where as at the concentration of 100% it showed good bacterial staining results because the bacteria was purple. Meanwhile, gram-negative e.coli bacteria isolates at the concentration of 60%, 70%, 80%, 90%, 100% showed good bacterial staining results because the bacteria were red. Suggestions for further research to do maceration longer.

Characterization of Anthocyanin Associated Purple Sweet Potato Starch and Peel-Based pH Indicator Films.

In food packaging, smart indicator films based on natural resources have greatly attracted researchers to minimize the environmental issues as well as to satisfy consumer preferences for food safety. In this research, pH-sensitive films were prepared using purple-fleshed sweet potato starch (SPS) and sweet potato peel (SPP). Two categories of the film (i) SPS and (ii) SPS/SPP, were fabricated via solvent casting technique, incorporating different concentrations of commercial purple sweet potato anthocyanin (CA) at 0%, 1%, 1.5%, and 2% (w/v) and the physicochemical, mechanical, thermal, and morphological properties of the films were investigated. The thickness, water solubility, and swelling degree of the films increased with the increment of CA, whereas there were no significant changes in the water content (WC) of the films. Water vapor permeability (WVP) was decreased for SPS films while statistically similar for SPS/SPP films. The addition of CA reduced the tensile strength (TS) and tensile modulus (TM) yet increased the elongation at break (EaB) of the films as compared to films without CA. The FTIR results confirmed the immobilization of anthocyanin into the film. In SEM images, roughness in the surfaces of the CA-associated films was observed. A reduction of thermal stability was found for the films with anthocyanin except for the SPS/SPP CA 2% film. Furthermore, the CA-associated films showed a remarkable color response when subjected to pH buffers (pH 1 to 12) and successfully monitored chicken freshness. The fastest color migration was observed in acidic conditions when the films were immersed into aqueous, acidic, low fat, and fatty food simulants. The findings of this work demonstrated that the developed pH indicator films have the potential to be implemented as smart packaging to monitor food freshness and quality for safe consumption.

CHARACTERIZATION OF THERMOSTABLE BETA-1,4-GALACTANASE AND ITS APPLICATION IN HYDROLYSIS OF PECTIN FROM SWEET POTATO (Ipomoea batatas (L.) Lam) PEELS

Galactooligosaccharides (GOS) synthesis has received much attention due to its prebiotic function. Beta-1,4-galactanase responsible for the hydrolysis of galactan plays an important role in producing GOS from biodegradation of this pectin component. In this study, beta-1,4-galactanase (BgcGC) from a thermophilic Geobacillus mahadii Geo-05 was heterologously expressed in Escherichia coli (E. coli) and characterized. The optimum temperature of BgcGC was at 60°C and stable from 20-60°C while optimum pH was at 6 and stable from pH 4-10. BgcGC showed high catalytic efficiency towards potato galactan (873.8 ml mg-1 s-1) and lupin galactan (1694.4 ml mg-1 s-1). The activity of BgcGC was not significantly affected with the presence of 100 mM K+, Tween-20 and 2-mercaptoethanol. Application of BgcGC towards pectin-containing galactan oligomer extracted from sweet potato peels resulted in galactose and GOS synthesis as revealed by high performance liquid chromatography analysis. Thus, this enzyme has a potential to be one of the enzyme candidates involves in pectin complex degradation to produce GOS.

Screening of Potential Tannase-producing Fungi from Local Agri-industrial By-products using a Plate Assay and Submerged Fermentation

Tannase (Tannin Acyl Hydrolase EC 3.1.1.20) is an industrial inducible enzyme capable of hydrolyzing hydrolyzable tannin ester linkage gallotannin and ellagitannin, producing gallic acid and glucose. Tannase is extensively used in the pharmaceutical, chemical, cosmetics, textile, leather, food, feed, and beverage industries. In the beverage industry, tannase is used as a clarifying agent to clarify tannin present in coffee, coffee-flavored soft drinks, tea, and fruit juices by removing phenolic compounds. In the pharmaceutical industry, tannase is used to produce gallic acid, an intermediary compound in the production of antibacterial drug, trimethoprim, while in the food industry, tannase is used to synthesize crucial antioxidant food preservative propyl gallate (3,4,5-trihydroxybenzoate). Most of the tannase production utilizes bacteria such as Bacillus sp. as tannase producer under submerged fermentation, SmF. Despite the immense industrial potential of tannase, it has not fully been exploited due to lack of knowledge, and fewer studies reported filamentous fungi for tannase production. This study aimed to screen potential tannase-producing fungi from various agri-industrial by-products such as rice by-products, spent tea, spent coffee ground, banana peels, mango peels, desiccated coconut residue, soybean residue, sweet potato peels, and onions. Fungal isolate, J1 (Aspergillus niger) was identified as the efficient tannase-producing fungus due to the hydrolytic zone's largest diameter (60.7 ± 0.6) mm. It achieved high tannase activity with (6.86 ± 0.04) U/ml in submerged fermentation, SmF. In conclusion, filamentous fungi isolated from agri-industrial by-products have huge potential as an efficient tannase producer.

Anthocyanins from Agro-waste as Time-Temperature Indicator to Monitor Freshness of Fish Products

Fish products perish easily due to microbial contamination. Uncontrolled thawing will increase the rate of microbial activity at every 10°C increase in temperature. One of indicator that can detect food quality is the time-temperature indicator (TTI) with changes in pH. However, these indicators are generally made of synthetic chemicals which tend to pollute the environment. This study aimed to summarize various studies on anthocyanins from agro-waste as time-temperature indicator to monitor freshness of fish products. This research used systematic literature review (SLR) from various relevant research and resources. The SLR process includes practical screening, quality appraisal, synthesizing, and reviewing. Anthocyanins derived from agro-waste than can be developed into TTI are purple yam peel, black plums peel, blueberries peel, rambutan peel, sweet potato peel, dragon fruit peel. The TTI from agro-waste anthocyanins can be developed to monitor freshness of fish products.

Arapey sweet potato peel waste as renewable source of antioxidant: extraction, nanoencapsulation and nanoadditive potential in films

In this work, the peel of Arapey Sweet Potato (Ipomoea batatas), a vegetable waste, was used as a source of phenolic compounds which are widely recognized as beneficial antioxidants for human health. The extract obtained from Ipomoea batatas exhibited an antioxidant activity significantly higher than many antioxidant agents reported in literature (476.96 mg of TROLOX mL-1), as well as good thermal stability. Nanocapsules of the extract coated with low molecular weight polylactic acid were prepared by the emulsification-solvent evaporation method and the nanoparticles obtained were characterized physical; thermal; and morphologically. An analysis of the variables that were investigated to increase the encapsulation efficiency is presented here. Besides, PLA films prepared via the solution-casting method exhibited good compatibility with the nanoparticles loaded with the antioxidant extract, as was evidenced by the uniform and stable dispersion of these particles in the films. Furthermore, an improvement of the mechanical properties of the PLA films due to the presence of the nanoparticles were clearly observed. Results reported here are encourage enough to propose the nanocapsules described in this work as additives or to be used immersed in films for controlled release of antioxidants, putting in value a vegetable waste.

Sweet Potato Peel Flour Applications in The Textural Quality of Waffle Ice Cream Cone and Other Food Products

Sweet potatoes are nutritious vegetables commonly grown in Malaysia. However, its beneficial skins are mostly peeled and thrown away. The sweet potato peel has a slightly bitter taste with its good nutritional food value in producing healthy food products. In this study, sweet potato peel flour (SPPF) is added to the existing wheat flour in the formulation of ice cream waffle cones. The amount of wheat flour added in the mixture depends on the SPPF amount added. Preliminary study on the content of protein, moisture, crude fiber, protein, carbohydrate and fat were conducted and determined. Then, the SPPF was added based on the formulation of 5%, 10% and 15% addition to the wheat flour at 95%, 90% and 85%, respectively, in a batter mix formulation for the making of ice cream waffle cones. The control was made out of 100% wheat flour, in order to compare with the newly formulated ice cream waffle cones batter mixture. Addition of SPPF has impacted the quality of waffle ice cream cone in regards to its physicochemical properties such as colour, odour, tensile strength and textural properties. As the results, waffle cones of SPPF had lower value of L*, a* and b*, which turned darker than a controlled sample. The 5% formulation of sweet potato peel flour (SPPF) resulted to the highest crispiness of the waffle cones. Tensile strength of fiber materials in sweet potato peels flour became stable and balanced with the cone structure. Overall SPPF formulated waffle cones have passed the physical analysis and food applications’ requirements. As the SPPF have high value in water holding capacity, it can contribute to other food applications.

Availability and estimation of crop by-product yields for small ruminant production in Cross River State, Nigeria

A study was carried out in some Local Government Areas of Cross River State of Nigeria to identify and ascertain the availability, level of production and the yields of crop by-products derived from commonly cultivated crops that can serve as feed for small ruminants. The results show that the various staple crops commonly grown in Cross River State produce the following crop by-products in a decreasing order of yields- cassava peels> yam peels> corn cobs> maize sheaths> plantain peels> maize offal> rice offal> cassava sievets> banana peels> fried garri sievets> groundnut haulms> sweet potato peels. The annual yield of crop by-products per Local Government Area is estimated as follows: cassava peels 89,226.40, yam peels 32,318.80, maize sheaths and offal 358,050.00, rice 0ffal 37,140.00, cowpea haulms 34,064.00, groundnut haulms 41,872.00, banana peels and rejects 18,420.00, plantain peels 7,598.40, cocoyam peels 11,944.00, sweet potato peels and rejects 8,024.00 tonnes per selected LGA.The total amount of crop by-products (638,657.60 tonnes) generated each year from the staple food crops will go a long way in solving the problem of feed scarcity for ruminants during dry season.

Quality of ensiled Guinea grass (Panicum maximum) at varying proportions with sweet potato peels for ruminant production in Niger Delta, Nigeria

Quality of ensiled Panicum maximum with different proportion of sweet potato peels for ruminant production was studied. Panicum maximum (PAM) were harvested at 4-week regrowth, chopped to 2-3 cm, wilted and ensiled with sweet potato peel (SPP) at different proportions (%) to have seven experimental treatments: T1 (100 PAM/ 0 SPP); T2 (90 PAM/ 10 SPP); T3 (80 PAM/ 20 SPP); T4 (70PAM/ 30 SPP); T5 (60 PAM/ 40 SPP; T6 (50 PAM/ 50 SPP); T7 (40 PAM/ 60 SPP). Bamma bottles (960mL) were used as laboratory silos. Each treatment had three replicates in completely randomize design. The ensiled materials were kept for 270 days. Physical characteristics, chemical composition and fiber fractions were examined. The colour observed were yellowish-green to olive-green, while the aroma was mild sweet in all the treatments except T3 and T6 with 20% and 5% mouldiness, respectively. Firm texture was recorded for all the treatments, while the pH values ranged from 2.9 – 3.7. There was a significant (P<0.05) difference in DM, CP, CF, ash, NFE, NDF, ADF and NFC except ether extract. There was no significant (P>0.05) different in the Ca, P, Na and Mg content of the silage. The value of Fe and Zn was significantly different (P<0.05) and ranged from 165.7 – 169.2 mg/kg and 22.30 – 23.70 mg/kg, respectively. There was a significant difference (P<0.05) in the 24hrs gas production, methane production (CH4), short chain fatty acid (SCFA), organic matter digestibility and metabolizable energy (ME), while similar (P>0.05) value was recorded for dry matter digestibility(DMD) and fermentation efficiency (FE) across the experimental treatments. The qualities recorded for the experimental treatments at the end of 270 days ensiled period, showed that the silage of Panicum maximum with different proportions of sweet potato peel especially T4 (70 PAM/30 SPP) could sustain ruminant production especially during the dry season.

Effect of sweet potato (Ipomoea batatas lam.) Peel meal as replacement for maize on growth performance and cost of feeding weaner rabbits

The experiment was carried out to determine the effect of replacement of maize with sweet potato (Ipomoea batatas lam.) on growth performance and cost of feeding weaner rabbits (Oryctolagus cuniculus). A total number of thirty-six (36) weaned rabbit of mixed sexes were used for the experiment. The rabbits were allotted randomly into four dietary treatments and replicated thrice with three rabbits per replicate and were designated: control (T): normal 1 compounded diet without sweet potato peel meal, T had the compounded feed which 5% 2 sweet potato peel meal, T had compounded diet with 10% sweet potato peel meal and 3 treatment four (T) had the compounded diet with 15% sweet potato peel meal. The 4 experiment lasted eight weeks and data were obtained on growth performance and cost benefit. The parameters considered on growth performance include initial weight, final weight, total body weight gain, daily weight gain, weekly weight gain, daily feed intake, total feed intake and feed conversion ratio while that of cost benefit include cost of purchasing different experimental feed stuff. The results obtained on growth performance showed that there were no significant differences (p>0.05) in the parameters monitored. Cost of feeding was also not significantly different (p>0.05). However, higher profit index (174. 64) was recorded in T1 and lower benefit cost ratio (166.68) was recorded in T4 for total cost of feed intake per rabbit. In conclusion, sweet potato peel meal can be uses as a good replacement for maize in rabbit production without any adverse effect on the performance of rabbit.

Preparation and Characterization of Colorimetric Indicator Films Based on Chitosan/Polyvinyl Alcohol and Anthocyanins from Agri-Food Wastes

This work aimed to compare the potential application of anthocyanins extracted from jabuticaba fruit (Plinia cauliflora) and purple sweet potato (Ipomoea Batatas L.) peels as potential raw materials to manufacture colorimetric indicator films. The effect of anthocyanin source on morphology, thickness, moisture content, hydrophobicity, solubility in water, chemical structure, thermal properties, color, and opacity of films was analyzed. Furthermore, color change of films when exposed to controlled visible light and their application to monitoring meat freshness at three temperatures (− 20, 4, and 20 °C) was studied. Anthocyanins from both agri-food wastes increased the molecular spacing in the polymer chains, increasing thickness values and decreasing the thermal stability of the films. However, this effect was more evident when anthocyanins from purple sweet potato peels were used. The other physicochemical properties of colorimetric films were not altered with the presence of anthocyanins. Both colorimetric indicator films showed visible changes from red color to blue color when used to monitor meat freshness at the proposed storage temperatures. Based on physicochemical and colorimetric results, jabuticaba peel is an interesting agri-food waste to manufacture colorimetric indicator films for the food packaging sector.

Encapsulation and Degradation Kinetics of Bioactive Compounds from Sweet Potato Peel During Storage.

SUMMARYResearch backgroundThe aim of this work is to evaluate utilization of sweet potato peel as a source of bioactive compounds. The effect of solvents (acetone and acetone/ethanol mixture) on the extraction efficiency of total carotenoids and phenolics from sweet potato tuber, flesh and peel, and antioxidant activity were investigated. Sweet potato peel extract stood out in terms of antioxidant activity and was chosen for encapsulation by spray and freeze-drying.Experimental approachEncapsulation is an effective method to improve phytochemical stability by entrapping the core material with a coating agent. In this study, spray and freeze-drying techniques were applied for improving the stability of bioactive compounds (carotenoids and phenolics) using whey protein as a coating material. The main advantages of the applied techniques over the other encapsulation techniques are simplicity, continuity, effectiveness, availability and applicability.Results and conclusionsPhysicochemical characteristics revealed that spray drying resulted in the formation of lower size particles, better flow properties and encapsulation efficiency of carotenoids. The retention of encapsulated and non-encapsulated bioactive compounds was monitored during storage in daylight and dark conditions. Storage conditions affected the carotenoid retention, whereas higher degradation rate of all samples was observable in daylight. Phenolic compounds exhibited higher retention in all investigated samples. Degradation kinetic parameters suggest the longer shelf life of spray dried encapsulated extract and potent method for stabilization of bioactive ingredients.Novelty and scientific contributionThis study demonstrates that the spray drying technique and utilization of sweet potato peel have a big potential for the development of functional additives with improved nutritional, colour and bioactive properties.

Optimization of media components and fermentation conditions for citric acid production from sweet potato peel starch hydrolysate by Aspergillus niger

This study investigated sweet potato peel waste as the main carbon source and determine the effect of media components and operating conditions on citric acid (CA) production by Aspergillus niger under submerged fermentation. The sweet potato peel waste is of low-cost readily-available and serve as hydrolysate for CA production. Two sets of experiments were performed using experimental design technique. The first set was designed using a low resolution 2-level factorial which was deployed for parameter screening. The other set of experiments was designed using 3-level design algorithm and was deployed for model development and optimization. The results from parameter screening showed that carbon source (CS), nitrogen concentration (NC), fermentation time (FT) and pH were the “heavy hitters” with significant impact on CA production. The developed model is predictive (R2 = 0.948) with optimum CA (3.22 mg/mL) obtained at CS (97.25%), NC (1.25%w/v), FT (7 days), and pH (6.5). This setting was validated experimentally and resulted in CA yield of 4.36 ± 006 mg/ml, representing a 135%-fold increase over the predicted yield. The present investigation shows that sweet potato peels hydrolysate is a viable and sustainable substrate for CA production.

PURPLE SWEET POTATO (Ipomoea batatas L.) PEELS EXTRACT AS AN ALTERNATIVE DYE FOR BACTERIA GRAM STAINING

Crystal violet and Safranin are dyes in Gram staining, which are carcinogenic. Alternative safe materials are needed to minimize the use of carcinogenic properties. Purple sweet potato (Ipomoea batatas L.) peels were the candidate of the alternative dye source because of its high anthocyanin pigment. The purpose of this study was to determine purple sweet potato (Ipomoea batatas L.) peels extract as an alternative to Gentian violet in Gram staining of bacteria. Extracts obtained from purple sweet potato peels studied with varying concentrations of 50%, 60%, and 75% for 1, 3, and 5 min as a substitute for Gentian violet on Bacillus sp. The parameters observed from this study based on visual field clarity, glass slide cleanliness, contrast, bacterial shape, bacterial colour. Each extract concentration compared with a control group using Gentian violet. The results showed that optimum staining in 50% concentration for 5 min, 60% concentration for 5 min, 75% concentration for 3 min, and 5 min respectively. The present study exhibited the potency of Ipomoea batatas L. peels extract as an alternative staining agent.

Optimization of polyphenols extraction from sweet potato peel: single factor versus chemometrics approach

The study was aimed at optimizing the extraction conditions of phenolic compounds from an orange-fleshed cultivar of sweet potato peel using a single factor vis-a-vis chemometric experimental approach. The effectiveness of extracting antioxidants compounds using an aqueous medium (water) was compared to organic solvents. Water-to-peel, time of extraction and extraction temperature was established to have significant effects on the total antioxidant and scavenging activities. Optimal extraction variables of 60 ºC for 20 minutes, at a solvent-to-peel powder ratio of 100:7.5 mL/g was derived for the process. Approximately 157.0 g of peel powder was obtained from a kilogram of the dried potato peel using a simple but scalable method. The polyphenol isolate contained 31.39 % polyphenols and compared significant well with vitamin C and butylated hydroxytoluene (BHT) in terms of its antioxidant activities. In summary, this study used an aqueous medium as its extracting solvent, which offers a great prospect for future use in the extraction and purification of bioactive compounds from plant materials.

Continuous Sorption of Chromium Ions from Simulated Effluents using Citric Acid Modified Sweet Potato Peels

Adsorptive removal of chromium ion in aqueous medium using activated sweet potato peel (SPP) was studied in a laboratory-scale fixed bed column. Specifically, the effect of process parameters such as bed depth, flowrate and chromium ion concentration in aqueous solution, on the adsorption efficiency of the acid modified sweet potato peel was examined. Column adsorption analysis showed that at the flow rate of 0.5 cm3/min, bed height of 6 cm and column influent concentration of 30 mg/dm3, the optimum chromium (VI) ion removal of 87.5% was attained with the equilibrium adsorption capacity of 2.4548 mg/g. Continuous adsorption models such as Yoon-Nelson, Adam-Bohart and the Bed-Depth Service Time (BDST) model, were used to analyse the experimental data and based on correlation coefficient, BDST model best aligned with the obtained experimental data with correlation coefficient, R2, value of 96.43%. The bed capacity, No, and the rate constant, Ka, were calculated as 4.259 mg/dm3 and 0.01045 L/mgmin respectively at optimum column conditions. Results confirmed that acid modified SPP can be used to remove or reduce concentrations of Cr (VI) ions to allowable limits before disposal into water bodies.
 Keywords: Continuous sorption, chromium ions, sweet potato peel, kinetic isotherms, breakthrough curves

Experimental Production of Biofuel using Lactose as an Enhancer to Aspergillus Niger and Saccharomyces Cerevisae

Nigeria is a rich nation in natural resources, which includes source of biofuel such as sweet potato starch etc. This starch can be converted to sugar through hydrolysis process in other to yield ethanol (biofuel). In this research work, the sweet potato peels was selected as a substrate for bioethanol production in the process, as it is rich in starch and cellulose. In this study, 5g, 10g, 15g, 20g and 25g each was weighed lactose and added to the Aspergillus Niger and Saccharomyces Cerevisae, the highest yield recorded when 20g of lactose was introduced. This achievement was observed after seven days, and the concentration of 91 ppm was highest for the sample containing 25g of lactose. The study also revealed that when lactose was added to fermentation medium together with enzyme Aspergillus Niger, the results obtained show that the 20g lactose represent a highest yield of biofuel production. In summary, the increase and subsequent decrease in pH and specific gravity of each fermented sample indicated that the reaction (fermentation) was actually occurred, that is, the conversion of the substrate to products as well as the release of CO2 as the by-product took place. Keywords: Aspergillus Niger, biofuel, starch and cellulose

Optimization of Pectin Extraction from Sweet Potato Peels Using Citric Acid and its Emulsifying Properties.

Pectin is a natural polysaccharide that has been used widely as a stabilizer in food emulsion system. This study aimed to optimize the yield of pectin extracted from sweet potato residue and investigate its emulsifying properties. Response surface methodology (RSM) has been utilized to investigate the pectin extracted from sweet potato peels using citric acid as the extracting solvent. Investigation of the effect of different extraction conditions namely temperature (°C), time (min) and solution pH on pectin yield (%) were conducted. A Box-Benhken design with three levels of variation was used to optimize the extraction conditions. The optimal conditions determined were temperature 76°C, time 64 min and pH 1.2 with 65.2% yield of pectin. The degree of esterification (DE) of the sweet potato pectin was determined using Fourier Transform Infrared (FTIR) Spectroscopy. The pectin is high-methoxyl pectin with DE of 58.5%. Emulsifying properties of sweet potato pectin were investigated by measuring the zeta-potential, particle size and creaming index with addition of 0.4 and 1.0 wt % pectin to the emulsion. Extraction using citric acid could improve the pectin yield. Improved emulsion stability was observed with the addition of the sweet potato pectin.

Microbial extraction of chitin from seafood waste using sugars derived from fruit waste-stream

Chitin and chitosan are natural amino polysaccharides that have exceptional biocompatibility in a wide range of applications such as drug delivery carriers, antibacterial agents and food stabilizers. However, conventional chemical extraction methods of chitin from marine waste are costly and hazardous to the environment. Here we report a study where shrimp waste was co-fermented with Lactobacillus plantarum subsp. plantarum ATCC 14917 and Bacillus subtilis subsp. subtilis ATCC 6051 and chitin was successfully extracted after deproteinization and demineralization of the prawn shells. The glucose supplementation for fermentation was replaced by waste substrates to reduce cost and maximize waste utilization. A total of 10 carbon sources were explored, namely sugarcane molasses, light corn syrup, red grape pomace, white grape pomace, apple peel, pineapple peel and core, potato peel, mango peel, banana peel and sweet potato peel. The extracted chitin was chemically characterized by Fourier Transform Infrared Spectroscopy (FTIR) to measure the degree of acetylation, elemental analysis (EA) to measure the carbon/nitrogen ratio and X-ray diffraction (XRD) to measure the degree of crystallinity. A comparison of the quality of the crude extracted chitin was made between the different waste substrates used for fermentation and the experimental results showed that the waste substrates generally make a suitable replacement for glucose in the fermentation process. Red grape pomace resulted in recovery of chitin with a degree of deacetylation of 72.90%, a carbon/nitrogen ratio of 6.85 and a degree of crystallinity of 95.54%. These achieved values were found to be comparable with and even surpassed commercial chitin.