Ultrasound-assisted Enzymatic Extraction Research Articles

Polysaccharides from Hericium erinaceus and its immunomodulatory effects on RAW 264.7 macrophages

This study aimed to optimize the extraction of Hericium erinaceus polysaccharides (HEP) using ultrasound-assisted enzymatic extraction combined with Plackett-Burman design (PBD) and response surface methodology (RSM). The optimal extraction conditions were identified as: 33 min extraction time, 30:1 liquid to material ratio, 38 °C extraction temperature, 9 g/kg cellulase amount, pH 4, and 20 % ethanol concentration. Under these conditions, the extraction yield of HEP was 5.87 ± 0.16 %, consistent with the predicted results. Additionally, the potential immunomodulatory activity of HEP on RAW 264.7 macrophage was evaluated. The results revealed that HEP improved the immunostimulatory activity of RAW264.7 cells, evident from increased production of IL-6 and TNF-α. These findings suggest that HEP is capable of enhancing the immune activity of RAW 264.7 macrophage.

Optimization of ultrasound-assisted enzymatic extraction, chemical constituents, biological activities, and stability of Camellia oleifera fruit shell brown pigments

The need for the use of natural pigments in food manufacturing rises steadily. However, the application of natural pigments is limited by costly production and poor stability. Hence, the brown pigments from Camellia oleifera shells (disposal from tea oil production) were focused on in this study. The enzymatic extraction of Camellia oleifera fruit shell brown pigment (BP-CS) with ultrasound assistance was optimized by Box-Behnken design to cut extraction expenses. The yield of BP-CS was 38.56% under the optimized extraction parameters as extraction time of 77 min, extraction temperature of 64 °C, cellulose concentration of 10 mg/mL and liquid-solid ratio of 20mL/g. Subsequently, for promising no harmful ingredients in BP-CS, all 36 compounds were identified, and the primary constituents were flavonoids (quercitrin, quercetin) and organic acids (D-malic acid, citric acid). Via stability analysis, the brown pigment was pretty stable under heating, pH, and sunlight changes while was impacted by metal ions and redox agent conditions. Additionally, BP-CS was able to scavenge free radicals (DPPH, ABTS, ·OH) and prevent the growth of microorganisms. Moreover, BP-CS could reduce α-amylase and tyrosinase activity, and both quenching mechanisms were static quenching. Overall, this work reveals that BP-CS is a valuable natural pigment, and is anticipated to be employed as a premium-quality pigment additive in the food industry.

Green valorization approach of Citrus limetta peels by ultrasound-assisted enzymatic extraction for recovery of dietary fibers: Optimization, physicochemical, structural, functional, and thermal properties

Green valorization approach of Citrus limetta peels by ultrasound-assisted enzymatic extraction for recovery of dietary fibers: Optimization, physicochemical, structural, functional, and thermal properties

Ultrasound-assisted enzymatic extraction of soluble dietary fiber from Hericium erinaceus and its in vitro lipid-lowering effect

Dietary fiber (DF) is an important active polysaccharide in Hericium erinaceus. Obesity can lead to a wide range of diseases. In this work, we investigated the in vitro lipid-lowering effect of soluble dietary fiber (SDF) from H. erinaceus, aiming to provide a basis for the subsequent development of lipid-lowering products. Ultrasound-assisted enzymatic extraction (UAEE) of SDF from H. erinaceus was performed. The optimal extraction parameters determined via single-factor experiments and response surface methodology (RSM) were as follows: Lywallzyme concentration, 1.0%; complex protease concentration, 1.2%; ultrasonication time, 35 min; and ultrasonication power, 150 W. In vitro lipid-lowering experiments revealed that the adsorption amount of cholesterol micelles by H. erinaceus SDF was 11.91 mg/g. The binding amount and binding rate of sodium taurocholate were 3.73 mg/g and 42.47%, respectively, and those of sodium glycocholate were 3.43 mg/g and 39.12%, respectively. The pancreatic lipase inhibition rate reached 52.11%, and the type of inhibition was competitive. Therefore, H. erinaceus SDF has good in vitro lipid-lowering ability.

Utilization of low-grade walnut kernels for oil extraction using eco-friendly methods: a comparative analysis of oil composition, antioxidant and antimicrobial activity

Walnut oil was extracted using three different eco-friendly extraction methods, solvent extraction (using ethyl acetate [EA] and ethanol [ET]), aqueous enzymatic extraction (AEE), and ultrasound-assisted enzymatic extraction (UAEE), and their lipid yield, lipid composition, physicochemical analysis, mineral composition, total phenols, antioxidant capacity, and antimicrobial activity were analyzed and compared. The AEE technique offered a greater yield (50.6%) than the other extraction methods and gave comparatively higher linoleic acid (66.12%) content. Palmitic, oleic, linoleic, linolenic, and stearic acids were the principal components that GC/MS detected in all the oil samples. UAEE produced the most polyphenols (0.49 mgGAE/g), followed by AEE (0.46 mgGAE/g), EA (0.45 mgGAE/g), and ET (0.35 mgGAE/g). The DPPH assay results were in the order of UAEE (191 μmolTE/kg) > AEE (186 μmolTE/kg) > EA (153 μmolTE/kg) > ET (130 μmolTE/kg). The FRAP assay findings showed a similar pattern: UAEE (112 molTE/kg) > AEE (102 molTE/kg) > EA (96 molTE/kg) > ET (82 molTE/kg). Results suggested that for a higher extraction yield, AEE is the better technique and UAEE is the recommended method for enhancing walnut oil antioxidant capacity. Additionally, it was found that polyphenols considerably increased the antioxidant capacity of walnut oil and are thought to be health-promoting. The results demonstrated the antibacterial effectiveness of the extracted oil against Bacillus subtilis, Bacillus licheniformis, and Staphylococcus aureus. This study provides information about low-cost and ecofriendly technologies of walnut oil extraction for food, cosmetic, and medical uses.

GREEN EXTRACTION OF CAROTENOIDS FROM LEMON PEELS

Nowadays, there is a growing interest in fully utilizing agro-industrial wastes, with carotenoids gaining attention as valuable coloring agents. One of the potential sources for carotenoid extraction is lemon peel. The purpose of this study was to determine optimal extraction techniques for extracting as much carotenoids as possible from lemon peel. In this context, a comparison was conducted among extracts obtained via conventional, ultrasound-assisted (UAE), and ultrasound-assisted enzymatic (UAEE) extraction methods. The highest carotenoid content (0.792±0.01 mg/L) was achieved with UAEE, while the lowest (0.493±0.01 mg/L) was obtained conventionally. UAEE exhibited the highest antioxidant activity values among three methods: 753.80±5.79 mg TE/L (ABTS), 624.64±10.52 mg TE/L (DPPH), and 186.64±1.66 μmol TE/L (FRAP). In conclusion, UAEE showed promise in extracting carotenoids from lemon peel. Thus, by carotenoid extraction using green technology from waste lemon peels, with higher added value, richer in terms of phenolic composition and antioxidant properties, has been obtained.

Recovery of carotenoids as bioactive compounds from peach pomace by an eco-friendly ultrasound-assisted enzymatic extraction

AbstractThe industrial processing of fruits generates by-products. These by-products serve as a source of valuable bioactive compounds. In this study, carotenoid was extracted from peach pomace (PP) by using the ultrasound-assisted enzymatic extraction (UAEE), an eco-friendly method. The process conditions ensuring the highest carotenoid content and b* color value for UAEE were detected by response surface methodology (RSM). To demonstrate the effectiveness of the ultrasonic process, enzymatic extraction was carried out at the optimum point. Physicochemical (pH, titratable acidity, total soluble solids), color (L*, a*, b*, chroma value (ΔC) and color difference (ΔE), total phenolic compound (TPC) and antioxidant activity analyses (ABTS and FRAP) were carried. When the analysis results evaluated, the highest b* color parameter, TPC (761.10 mg gallic acid/L), ABTS (1933.33 mg Trolox/L) and FRAP (52.66 µmol Trolox/L) results of the extracts was observed with UAEE method. The study shows that ultrasound based upon the cavitation event was increased efficiency of enzymatic reaction with higher extraction yield and this provided in higher amounts of carotenoid and bioactive compounds. In other respects, when obtained carotenoid extracts are used in food formulations compatible with their acidic structure, they will contribute to protection of the product and minimizing color losses.

Valorization of Hakka Huangjiu lees: Optimization of ultrasound-assisted enzymatic extraction and identification of angiotensin I-converting enzyme inhibitory peptides

Angiotensin I-converting enzyme (ACE) inhibitory peptides of natural origin have attracted wide attention due to their easy metabolism and low toxicity. The aim of this study is to effectively utilize Hakka Huangjiu lees (HHL) to prepare peptides with high ACE inhibitory activity. In this study, ultrasound-assisted enzymatic extraction of peptides from HHL was optimized using single-factor and response surface experiments. Subsequently, the HHL hydrolysate was further isolated and purified based on the ACE inhibitory activity by ultrafiltration and chromatography methods. Finally, the molecular docking was used to explore the relationship between peptide structure and function. The results showed that the optimal extraction conditions were ultrasonic time 10 min, ultrasonic power 200 W, alcalase/substrate ratio (E/S) 6000 U/g, and enzymatic hydrolysis time 4 h. Under the optimal conditions, the extraction rate of peptides from dried and defatted HHL was 31.25 %, which was comparable to the 7.10 % of the raw materials. Subsequently, three novel ACE inhibitory peptides were prepared from HHL hydrolysate and were identified as Ser-Asn-Tyr-Phe-Pro-Arg-Pro-Trp (SNYFPRPW), Trp-Leu-Gly-Tyr-Pro-Arg (WLGYPR), and Asp-Leu-Arg-Tyr-Trp (DLRYW), with the IC50 values of 45.36, 31.16 and 24.32μM, respectively. In addition, the three peptides all had high ACE activity, which was due to their effective interaction with the ACE active site through hydrogen bonding and hydrophobic interactions. Therefore, the ACE inhibitory peptides extracted from HHL, especially SNYFPRPW, WLGYPR and DLRYW, can be valuable candidates for the production of antihypertensive nutraceuticals and functional foods, providing the basis for alternative valorized product streams in the fermentation industry.

Ultrasound assisted intensified enzymatic extraction of total phenolic compounds from pomegranate peels

Pomegranate peels contain a considerable amount of bioactive chemicals, such as phenolic compounds including gallic acid and ellagic acid. The current study aims to optimize the extraction of total phenolic content (TPC) and its antioxidant capacity from a Pomegranate peel using various approaches involving enzyme and ultrasound, also focusing on process intensification using combination. The optimal parameters for ultrasound treatment were established as treatment time of 25 min, 130 W power, 50 % duty cycle, and a liquid–solid ratio of 50:1 at a fixed 22 kHz frequency, resulting in maximum TPC (21.521 mg GAE/ml) and antioxidant capacity (17.962 mg GAE/ml). Similarly, enzymatic treatment was optimized resulting in best conditions of a time of 55 min, 50 °C as temperature, pH of 5, and a 2 % enzyme concentration. Ultrasound-assisted enzymatic extraction (UAEE) experiments revealed that combining 25 min of ultrasonic treatment with 25 min of enzymatic treatment yielded the highest TPC (30.608 mg GAE/ml) and antioxidant capacity (27.703 mg GAE/ml). It was clearly demonstrated that UAEE outperformed EAE and UAE in terms of Total Phenolic Compound extraction and antioxidant capacity, with the order of efficiency being UAEE > EAE > UAE.

Study on the Optimization, Extraction Kinetics and Thermodynamics of the Ultrasound-Assisted Enzymatic Extraction of Tremella fuciformis Polysaccharides.

In this study, Tremella fuciformis polysaccharides (TFPs) were extracted by ultrasound-assisted enzymatic extraction (UAE) at different extraction parameters in order to explore the potential of ultrasound in intensifying the extraction yield. The effects of experimental conditions on the extraction yields were optimized using response surface methodology, with the optimal ultrasonic power of 700 W, temperature of 45 °C and time of 50 min. The kinetic analysis revealed that UAE significantly promoted the dissolution, diffusion and migration with the maximum yield of 26.39%, which was enhanced by 40.45% and 156.96% compared with individual ultrasonic extraction (UE) and enzymatic extraction (EE). According to the modified Fick's second law of diffusion, the extraction process of TFPs illustrated a good linear correlation (R2 ≥ 0.9), and the rate constant gradually elevated as the temperature increased from 25 to 45 °C, while the presence of ultrasound exerted a vital role in extracting TFPs. Regarding to the thermodynamic results, the positive values of ΔH and ΔG demonstrated that UAE, UE and EE were endothermic and unspontaneous processes. This study provides a theoretical basis for polysaccharide extraction processing.

Ultrasound-assisted enzymatic extraction of polysaccharides from Paulownia flowers: process optimization, structural characterization, antioxidant and hypoglycemic activities

This study aimed to optimize the ultrasound-assisted enzymatic extraction (UAEE) process of Paulownia flowers polysaccharides (PFP) and investigate its antioxidant and hypoglycemic activities. The optimal extraction conditions were cellulase dosage 1.6 mg/g, liquid-solid ratio 27:1mL/g, ultrasonic power 230 W, temperature 51 °C, the PFP yield reached 5.50 % which was close to the predicted value of 5.59 %. Furthermore, the PFP was isolated and purified by DEAE-52 cellulose column and sephadex G-200 column to obtain two polysaccharide fractions, PFP1-1 and PFP2-1. The characteristics, antioxidant activity and hypoglycemic activity of PFP1-1 and PFP2-1 were analyzed. PFP1-1 with a molecular weight of 52.8 kDa was mainly composed of mannose and glucose (molar ratio1.00:5.05), and PFP2-1 with a molecular weight of 8.768 kDa was consisted of mannose, rhamnose, glucuronic acid, glucose (molar ratio 1.00:7.41:8.09:11.30). Compared to PFP1-1, the antioxidant activity assays showed that PFP2-1 exhibited stronger DPPH radical, hydroxyl radical and superoxide radical scavenging capacity and the inhibitory activities revealed that PFP2-1 could more effectively inhibit α-amylase and α-glucosidase, which might be attributed to the uronic acid and low molecular weight in PFP2-1. This work will provide a foundation for the efficient extraction of PFP and utilization for antioxidant agent and digestive enzymes inhibitor of diabetes.

Environmentally Friendly Approaches for Extraction from Plant Material through the View of the Ultrasound-Assisted Enzymatic Extraction Operating Conditions

Increasing the shelf life of foods is one of the most important trends in food biotechnology. Extracts of aromatic plants have natural antioxidants and antimicrobial properties that can extend the shelf life of food. This study aims to improve the extraction efficiency of extracts from rosemary and a mixture of black cumin and oregano. It was found that the highest value of antioxidant activity (96.78%) was when extracts were obtained from rosemary using ultrasound-assisted enzymatic extraction according to the following parameters: (45℃-30min the dose of the mixture of enzymes cellulase + pectinase: 0.5 g in the ratio 1:1, processing mode 22.5kHz, power 400watts), also it was observed that the highest content of total phenols (148.56mg GAE/gram) and flavonoids (37.45mg QE/gram), was when extracts were obtained from rosemary, a mixture of herbs (black cumin and oregano), respectively according to the following parameters: (55℃-30min – the dose of the mixture of enzymes cellulase + pectinase: 0.5 g in the ratio 1:1, processing mode 22.5kHz, power 400watts). The results obtained confirm the high potential of using this technology in the food industry

In Vitro Stability of ACE-Inhibitory Peptides of Rohu Fish Waste to Heat, pH and Gastrointestinal Enzymes

Angiotensin-I converting enzyme inhibitory (ACEi) peptides were prepared from rohu (Labeo rohita) fish wastes by enzymatic hydrolysis [1.1% alcalase concentration (v/w); 130 min time; 52°C temperature and 0.8:1 solid-liquid ratio]. Ultrasound Assisted Enzymatic Extraction (UAEE) and Microwave Assisted Enzymatic Extraction (MAEE) were performed to enhance degree of hydrolysis (DH), ACEi activity, and peptide yield (PY). The ACEi peptides were examined for stability during thermal processing, varied pH treatments and in vitro gastrointestinal digestion. Peptides were stable at different temperatures (25, 37, 55, 75, and 100°C) except at 121°C which reduced their stability by 7%, 6.9% and 2.2% in UAEE, MAEE and Non-Assisted Enzymatic Extraction (NAEE) peptides, respectively. Similarly, peptides retained ACEi at pH 2 to 8 and subsequent reduction at pH>8. In vitro digestion studies showed stability of all peptides to GI digestion at 0.05% pepsin, 0.05% trypsin, 0.05% chymotrypsin and the combination of 0.025% trypsin and 0.025% chymotrypsin except MAEE peptides showing less stability with pepsin (0.05%). Therefore, it is concluded that these ACEi peptides derived from rohu fish waste, stable to heat, pH and gastrointestinal enzymatic action, can be used as ingredient in functional foods, which undergo thermal processing and digestion.

Characterization of Proteins Extracted from Ulva sp., Padina sp., and Laurencia sp. Macroalgae Using Green Technology: Effect of In Vitro Digestion on Antioxidant and ACE-I Inhibitory Activity.

Macroalgal proteins were extracted from Ulva rigida (URPE) (green), Padina pavonica (PPPE) (brown), and Laurencia obtusa (LOPE) (red) using ultrasound-assisted enzymatic extraction, which is one of the green extraction technologies. Techno-functional, characteristic, and digestibility properties, and biological activities including antioxidant (AOA) and angiotensin-I converting enzyme (ACE-I) inhibitory activities were also investigated. According to the results, the extraction yield (EY) (94.74%) was detected in the extraction of L. obtusa, followed by U. rigida and P. pavonica. PPPE showed the highest ACE-I inhibitory activity before in vitro digestion. In contrast to PPPE, LOPE (20.90 ± 0.00%) and URPE (20.20 ± 0.00%) showed higher ACE-I inhibitory activity after in vitro digestion. The highest total phenolic content (TPC) (77.86 ± 1.00 mg GAE/g) was determined in LOPE. On the other hand, the highest AOACUPRAC (74.69 ± 1.78 mg TE/g) and AOAABTS (251.29 ± 5.0 mg TE/g) were detected in PPPE. After in vitro digestion, LOPE had the highest TPC (22.11 ± 2.18 mg GAE/g), AOACUPRAC (8.41 ± 0.06 mg TE/g), and AOAABTS (88.32 ± 0.65 mg TE/g) (p < 0.05). In vitro protein digestibility of three macroalgal protein extracts ranged from 84.35 ± 2.01% to 94.09 ± 0.00% (p < 0.05). Three macroalgae showed high oil holding capacity (OHC), especially PPPE (410.13 ± 16.37%) (p < 0.05), but they showed minimum foaming and emulsifying properties. The quality of the extracted macroalgal proteins was assessed using FTIR, SDS-PAGE, and DSC analyses. According to our findings, the method applied for macroalgal protein extraction could have a potential the promise of ultrasonication application as an environmentally friendly technology for food industry. Moreover, URPE, PPPE, and LOPE from sustainable sources may be attractive in terms of nourishment for people because of their digestibility, antioxidant properties, and ACE-I inhibitory activities.

Optimization of ultrasound-assisted enzymatic extraction of betalains from red beetroot (Beta vulgaris L.)

Betalains in red beetroot (Beta vulgaris L.) offer health benefits and are commonly used as a food colorant. This study aimed to investigate betalains extraction using ultrasound-assisted enzymatic extraction (UAEE). The most significant factors involved in UAEE such as enzyme concentration, extraction temperature, and extraction time were studied and optimized using the response surface method (RSM) to achieve the highest betalains yield. The results showed that the optimal extraction conditions were as follows: enzyme concentration (32.1 U/mL), extraction temperature (40oC), and extraction time (117 min) gave the highest yield of betalains at the level of 550.51 ± 25.76 mg/L. The findings are promising for the industrial scale of extraction betalains for food applications.

Optimization of fucoidan recovery by ultrasound-assisted enzymatic extraction from South African kelp, Ecklonia maxima

Fucoidan, a sulphated polysaccharide, is found exclusively in brown seaweeds and has been reported to possess a wide range of biological functionalities. Fucoidans are found within the cell wall of brown seaweeds, which is composed of recalcitrant cellulose and hemicellulose. This hampers the recovery of fucoidans. In addition, fucoidans are found within a network of viscous hydrocolloids, alginates, further complicating their recovery. Traditionally, the hot water extraction method is used to recover fucoidans from brown seaweed, however, this is characterized by low yields and long extraction time. To combat these issues, several novel extraction technologies have been introduced, these include ultrasound-assisted extraction and enzyme-assisted extraction. Thus, the main aim of this study was to investigate and optimize fucoidan recovery from Ecklonia maxima based on ultrasound-assisted enzymatic extraction. The impact of temperature (40–65 °C), ultrasound intensity (0–118 W·cm−2), enzyme dosage (0–0.05 ml·g−1) and pH (4.5–6) on total dissolved, total carbohydrates and inorganic sulphates yields was studied. The application of ultrasound-assisted enzymatic extraction mainly improved the extraction of total carbohydrates. Ultrasound significantly improves the kinetics and extraction of fucoidan, but there was no merit when it was applied with enzymes. Results reveal that at optimized conditions, the fucoidan extracted 79.13 mg⋅g−1 (7.9 % w/w) of algal dry weight. The present study provides insight into the extraction potentials of enzyme-assisted extraction, ultrasound-assisted extraction, and ultrasound-assisted enzymatic extraction.

Ultrasound-assisted enzymatic extraction, structural characterization, and anticancer activity of polysaccharides from Rosa roxburghii Tratt fruit

In this work, Rosa roxburghii Tratt fruit polysaccharides (RPs) were extracted by ultrasound-assisted enzymatic method. The highest extraction yield of RPs was 4.78 ± 0.10 % under the optimal extraction conditions. Two purified fractions named RP1 and RP3 were obtained and systematically characterized by a combination strategy of FT-IR, monosaccharide composition, molecular weight distribution, methylation and 2D NMR spectroscopy analyses. Structural analysis showed that the main chain of RP1 was composed of rhamnogalacturonan type I (RG-I), while the side chains were rich in arabinogalactan and galactose. RP3 was composed of long homogalacturonan (HG) backbone interspersed with alternating sequences of RG-I domains, with galactose and arabinose side chains. RP1 and RP3 induced apoptosis of MCF-7 cells in a dose dependent manner in vitro especially for RP1, and had no effect on L929 cells. Furthermore, the possible anticancer mechanisms were revealed, and results suggested that RP1 induced apoptosis through ROS-dependent pathway and mitochondrial pathway. The results of this work not only provided an efficient extraction method and theoretical basis for the application of RPs, but also may contribute to develop novel functional foods or pharmaceutical products for the prevention and treatment of human breast cancer disease.

Effects of different extraction methods on physicochemical characteristics and bioactivities of fig (Ficus carica L.) leaves polysaccharides

The tea of fig (Ficus carica L.) has long been used as a medicine in China due to its excellent effects on hemorrhoids, damp heat diarrhea and other diseases. The present study was designed to evaluate the impacts of different extraction methods, including hot water extraction (HWE), microwave assisted extraction (MAE), ultrasound assisted extraction (UAE), ultrasound assisted enzymatic extraction (UAEE), ultrasound-microwave assisted extraction (UMAE), alkali extraction (AE) and high-speed shearing homogeneous extraction (HSHE), on physicochemical characteristics and bioactivities of polysaccharide from fig leaves (FLPs). Results indicated that there were great differences between the structure and activity of FLPs prepared by seven methods. Among them, FLPs extracted by UAE (FLPs-UAE) showed the strongest antioxidant and hypoglycemic activities due to its higher Mw, total polysaccharide content (60.62 ± 3.06 %) and glucosamine (GlcN) content (7.68 %). In addition, FLPs extracted by HWE possessed more total polysaccharide content (62.03 ± 0.70 %), total phenolic compounds content (13.55 ± 0.02 %) and GlcN content (5.78 %) contributed to its strong antioxidant activity and the inhibition on α-amylase and α-glucosidase, which was second to FLPs-UAE. These finding suggested that UAE and HWE, especially UAE, were good ways to extract FLPs with high antioxidant and anti-diabetic activities, which provide foundations for choosing the suitable extraction strategy to prepare FLPs with desired bioactivities and promoting the application of FLPs in function food industries.

Ultrasound-assisted enzyme extraction and properties of Shatian pomelo peel polysaccharide

In this study, Shatian pomelo peel was used as the raw material for extracting polysaccharides using hot water extraction (HW) and ultrasonic-assisted enzyme (UVE) methods, respectively. The optimal parameters for extractingShatian pomelo peel polysaccharides (StPP) using the ultrasound-assisted enzymatic method were determined using response surface methodology (RSM). The optimal conditions for the extraction of StPP were as follows: ultrasound power 350 W, ultrasound time 50 min, enzymatic digestion time 50 min, compound enzyme addition 1.5%, and enzymatic digestion temperature 55 °C. The yield of StPP was found to be 30.1310% under these conditions. Comparing the physicochemical properties and antioxidant activity of StPP extracted using different methods, it was observed that ultrasound-assisted enzyme extraction resulted in higher yield, sugar content and glucuronic acid content of StPP compared to traditional hot water extraction. Additionally, StPP extracted by ultrasound-assisted enzyme extraction showed better antioxidant activity. These results suggest that ultrasound-assisted enzymatic extraction is an effective method to enhance the activity of natural polysaccharides.

Extraction of dietary fiber from kinnow (Citrus reticulata) peels using sequential ultrasonic and enzymatic treatments and its application in development of cookies

The paradigm shifts from discarding horticulture byproducts to exploiting them for their bioactive potential has encouraged research on non-conventional extraction techniques such as extraction using microwave, ultrasound, high-pressure, etc. Kinnow peels, a primary residue of kinnow processing industry, are profuse with polysaccharides, such as dietary fiber which can be isolated and used as a functional ingredient in fortified/enriched foods. In the present study, ultrasound-assisted extraction (UAE) and ultrasound-assisted-enzymatic extraction (UAEE) have been optimized to maximize dietary fiber yield from kinnow peel waste. Total dietary fiber (TDF) of 52.042 ± 0.862% was observed using UAE at 38% amplitude, liquid to solid ratio (LSR) of 40 mL/g, at 44 °C, after sonication time of 13 min, which increased to 60.974 ± 0.827% upon sequential enzymatic treatment. The WHC, OHC, and GAC of extracted dietary fiber ranged between 8.17 and 9.24 ± 0.11 g/g, 2.96–4.68 ± 0.09 g/g, and 1.56–2.28 ± 0.04 mmol/g. The physicochemical characterization of dietary fiber using analytical instruments and its functional properties such as oil/water holding, and glucose adsorption capacities proved that kinnow peels dietary fiber can be used to develop fiber-enriched products. The extracted fiber has been used to develop cookies which showed good nutritional, sensory, and textural properties with an overall acceptability of 7.15–7.84. This research will be helpful in scale-up studies on the valorization of different citrus peels through an extraction approach.