Microplastic contamination in salt-cured fish and commercial sea salts: an emerging food safety threat in relation to UN Sustainable Development Goals (SDGs).

Microplastic (MP) contamination in seafood, particularly processed varieties like dried and salt-cured fish, poses a significant threat to human health. This study investigated MP levels in 22 salt-cured fish species and commercial sea salts along the Indian east coast. Results showed substantially higher MP concentrations compared to global averages, with fragments and fibres (< 250 µm) composing 70% of identified MPs, primarily PVC and PS polymers (> 55%). Station 2 exhibited high pollution levels, with salt-cured fish averaging 54.06 ± 14.48 MP items/g and salt containing 23.53 ± 4.2 MP items/g, indicating a high hazard risk index. A modest correlation was observed between MP abundance, morphotypes, polymer composition in the salt, and their impact on fish products. Given the critical link between food safety, security, and public health, further research is imperative to mitigate MP contamination, aligning with UN Sustainable Development Goals (Goal 2, Goal 3, Goal 14, and Goal 15) for enhanced food safety and security.

Extraction, optimization, and functional quality evaluation of carotenoproteins from shrimp processing side streams through enzymatic process.

The study aimed to develop an effective and eco-friendly enzymatic process to extract carotenoproteins from shrimp waste. The optimization of enzymatic hydrolysis conditions to maximize the degree of deproteinization (DDP) of carotenoprotein from shrimp head waste (SHW) and shrimp shell waste (SSW) was conducted separately using the Box-Behnken design of response surface methodology (RSM). To achieve a maximum DDP of 92.32% for SSW and 96.72% for SHW, the optimal hydrolysis conditions were determined as follows: temperature (SSW: 53.13 °C; SHW: 45.90 °C), pH (SSW: 7.13; SHW: 6.78), time (SSW: 90 min; SHW: 61.18 min), and enzyme/substrate ratio (SSW: 2 g/100 g; SHW: 1.18 g/100 g). The carotenoprotein effluent obtained was subjected to spray drying and subsequently assessed for color, nutritional, and functional characteristics. The carotenoprotein from shrimp shell (CpSS) contained a higher essential amino acid score than carotenoprotein from shrimp head (CpSH). CpSS had a higher whiteness index of 82.05, while CpSH had 64.04. Both CpSS and CpSH showed good functional properties viz solubility, emulsion, and foaming properties. The maximum solubility of CpSH and CpSS was determined to be 92.94% and 96.48% at pH 10.0, respectively. The highest emulsion capacity (CpSH: 81.33%, CpSS: 70.13%) and stability (CpSH: 57.06%, CpSS: 63.05%) were observed at 3% carotenoprotein concentration. Similarly, the highest values of foaming capacity (CpSH: 27.66%, CpSS: 105.5%) and stability (CpSH: 23.83%, CpSS: 105.33%) were also found at the same 3% carotenoprotein concentration. In conclusion, the carotenoproteins obtained from shrimp waste showed favorable attributes in terms of color, amino acid composition, and functional properties. These findings strongly suggest the potential applicability of CpSS and CpSH as valuable resources in various domains. CpSS, with its higher whiteness index, greater amino acid content, and superior functional characteristics, may find suitability as functional ingredients in human food products. Conversely, CpSH could be considered for incorporation into animal feed formulations.

Harnessing value and sustainability: Fish waste valorization and the production of valuable byproducts.

The valorization of by-products, that are residual materials resulting from commercial product manufacturing, holds significant potential in various industries such as food, agrochemical, medical, and pharmaceutical sectors. This chapter explores the utilization of fish waste as a means to achieve sustainability in fish resources and enhance the production of profitable products. By developing cost-effective technologies, the abundant global supply of fish by-products can be transformed into low-cost sources of proteins and functional hydrolysates. This alternative approach in the food industry utilizes fish and seafood waste to generate valuable compounds with nutritional and functional properties, surpassing those found in traditional mammal products. Despite being commonly discarded, fish heads, viscera, skin, tails, blood, and seafood shells contain a wealth ofminerals, lipids, amino acids, polysaccharides, and proteins suitable for human health applications. This chapter presents an exploration of the various products and bioactive compounds that can be derived from seafood waste, contributing to a more sustainable and value-driven future.

Optimized high-yield synthesis of chitin nanocrystals from shrimp shell chitin by steam explosion.

This study attempted for the first time to prepare chitin nanocrystals (ChNCs) from shrimp shell chitin using steam explosion (SE) method. Response surface methodology (RSM) approach was used to optimize the SE conditions. Optimum SE conditions to acquire a maximum yield of 76.78 % were acid concentration (2.63 N), time (23.70 min), and chitin to acid ratio (1:22). Transmission electron microscopy (TEM) revealed the ChNCs produced by SE had an irregular spherical shape with an average diameter of 55.70 ± 13.12 nm. FTIR spectra showed ChNCs were slightly different than chitin due to a shift in peak positions to higher wavenumber and higher peak intensities. XRD patterns indicated ChNCs were a typical α-chitin structure. Thermal analysis revealed ChNCs were less thermally stable than chitin. Compared to conventional acid hydrolysis, the SE approach described in this study is simple, fast, easy, and requires less acid concentration and acid quantity, making it more scalable and efficient for synthesizing ChNCs. Furthermore, the characteristics of the ChNCs will shed light on the potential industrial uses for the polymer.

Process optimization and evaluation of the effects of different time-temperature sous vide cooking on physicochemical, textural, and sensory characteristics of whiteleg shrimp (Litopenaeusvannamei).

The objective of the current study was to optimize the cook-chill conditions of high-value whiteleg shrimp (Litopenaeus vannamei) processed using the sous vide (SV) technique and to assess the effects of various time-temperature combinations on the physicochemical, textural, and sensory qualities. For optimization, a Response Surface Methodology (RSM) approach utilizing a Central Composite Design (CCD) was adopted. Optimum SV cooking conditions to acquire minimum texture (hardness) of 7235 g was 13.48 min and 81.87 °C, expressible moisture of 18.48% was 14.5 min and 84.5 °C, and cook loss of 5.58% was 5 min and 75 °C. Texture (hardness) and expressible moisture decreased while cooking loss increased with increasing time-temperature treatment. Redness and yellowness values increased (p < 0.05) with increasing SV cooking time-temperature, but lightness values were nearly consistent in all treatments. With increasing time and temperature, TBARs and total carotenoid content increased (p < 0.05). However, the TBARs values were within accepted limits and ranged from 0.05 to 0.08 mg malonaldehyde/kg. Sensory evaluation indicated that all SV cooked samples were well accepted, with overall scores ≥7. These results suggest that the SV cooking temperature and time had a substantial impact on the textural, physicochemical, and sensory characteristics of shrimp. In addition, increasing time-temperature increased cooking and moisture loss, but decreased hardness and higher sensory scores made the product more acceptable to consumers.

Comparative efficiency of native and non-native starter culture in the production of bio-silage using composite waste from fish and vegetables.

The efficiency of native and non-native starter cultures in the production of bio-silage using composite waste from fish and vegetables was studied. An ensilage experiment was conducted in a natural way (without starter culture) of composite waste (fish to vegetable at 80 to 20%) to isolate the native fermentative microflora. An Enterococcus faecalis strain isolated from the natural ensilage of composite waste showed higher efficiency over other commercial LAB strains generally used for ensilation. A total of 60 isolates were screened and characterized biochemically from ensilaged composite waste. Among them, 12 proteolytic and lipolytic positive isolates were identified as Enterococcus faecalis, based on a BLAST search of the 16S rRNA gene sequences. Subsequently, composite bio-silage was prepared by inoculating starter cultures with three (3) treatments T1 (native-Enterococcus faecalis), T2 (non-native-Lactobacillus acidophilus), T3 (a mixture of E. faecalis and L. acidophilus) and compared with control (composite bio-silage without starter culture). The highest non-protein nitrogen (0.78 ± 0.01 mg of N /100 g) and degree of hydrolysis (70.00 ± 0.06% of protein/100 g) was seen in the T3 sample, and the lowest (0.67 ± 0.02 mg of N/100 g and 50.40 ± 0.04% of protein/100 g) was seen in the control. At the end of ensilation, the pH fell (5.95-3.88) in conjunction with the formation of lactic acid (0.23-2.05 g of lactic acid/100 g), and the lactic acid bacteria count nearly doubled (log 5.60-10.60). The lipid peroxidation products PV (0.11-0.41 milli equivalent of oxygen/kg of fat) and TBARs (1.64-6.95 mg of malonaldehyde/kg of silage) were changed within a reasonable range in the following pattern Control > T2 > T3 > T1, which led to oxidatively stable products. The findings revealed that native starter culture E. faecalis, which can be employed as a single or in combination with non-native L. acidophilus, performed better in the bio-ensilation process. Additionally, the finished composite bio-silage can be used as a novel, protein-carbohydrate rich feed component to help manage wastes from both sectors.

Microplastic contamination in salted and sun dried fish and implications for food security - A study on the effect of location, style and constituents of dried fish on microplastics load.

The presence of microplastics in 21 different species of marine dried fish products from four locations in India is reported in this study. All samples have microplastics, and majority of the MPs were found to be fragments (56 %) and are of <100 µm size (47 %). Eviscerated fish found to have significantly higher MPs than whole fish. Micro FTIR spectroscopy was used to recognize the polymer of identified MPs, which included polypropylene (21 %), low density polyethylene (17.5 %), polystyrene (15.5 %), and others. Anguilla bengalensis from station 1 had the greatest concentration of microplastics (99 ± 18.91 MPs/g) among all the samples. High value of microplastics polymer induced risk index (H) of different stations, suggesting a significant level of threat to consumer safety. Additional research is required to determine the potential effects on human health caused by consuming dried fish that contains variety of microplastics and their associated compounds.

Chitosan Gel Prepared with Citric Acid as the Food Acidulant: Effect of the Chitosan Concentration and Gel pH on Physicochemical and Functional Properties of Fish Protein Emulsion Sausages.

Citric acid is a popular food acidulant with versatile utility as a preservative and acidity regulator in the meat industry, owing to its unique three pK a values, which can be combined with the natural biopolymer chitosan to improve food quality. The scientific incorporation of a minimal range of chitosan and pH through organic acid additions for chitosan solubilization in the fish sausages can effectively improve their quality through their synergistic effect. Optimum conditions for emulsion stability, gel strength, and water holding capacity were found to be at a low concentration of chitosan, that is, 0.15 g at pH of 5.0, with their corresponding values of 42.55 ± 0.43 N mm, 94.91 ± 0.24, and 90.67 ± 0.50%. Lower pH ranges increased hardness and springiness values, and higher pH levels increased cohesiveness values at varying ranges of chitosan. Sensory analysis revealed tangy and sour flavors in the samples with lower pH.

Microcapsules of Shrimp Oil Using Kidney Bean Protein Isolate and κ-Carrageenan as Wall Materials with the Aid of Ultrasonication or High-Pressure Microfluidization: Characteristics and Oxidative Stability.

Emulsions containing shrimp oil (SO) at varying amounts were prepared in the presence of red kidney bean protein isolate (KBPI) and κ-carrageenan (KC) at a ratio of 1:0.1 (w/w). The emulsions were subjected to ultrasonication and high-pressure microfluidization to assist the encapsulation process. For each sample, ultrasonication was carried out for 15 min in continuous mode at 80% amplitude, whereas high-pressure microfluidization was operated at 7000 psi for 10 min. Ultrasonicated and microfluidized emulsions were finally spray-dried to prepare KBPI-KC-SO microcapsules. Moderate to high encapsulation efficiency (EE) ranging from 43.99 to 89.25% of SO in KPBI-KC-SO microcapsules was obtained and the microcapsules had good flowability. Particle size, PDI and zeta potential of KBPI-KC-SO microcapsules were 2.58-6.41 µm, 0.32-0.40 and -35.95--58.77 mV, respectively. Scanning electron microscopic (SEM) images visually demonstrated that the wall material/SO ratio and the emulsification method (ultrasonication vs microfluidization) had an impact on the size, shape and surface of the KBPI-KC-SO microcapsules. Encapsulation of SO in microcapsules was validated empirically using Fourier transform infrared (FTIR) analysis. Encapsulation of SO in KBPI-KC microcapsules imparted superior protection against oxidative deterioration of SO as witnessed by the higher retention of polyunsaturated fatty acids (PUFAs) and astaxanthin when compared to unencapsulated SO during extended storage at room temperature.

Comparative analysis of unwashed and single washed mince gel from Indian major carps.

The gelling properties and quality characteristics of unwashed and single washed mince of catla, rohu and mrigal have been investigated to find out suitability of Indian major carps for the preparation of mince gel. The higher moisture content and lower protein content was reported in the single washed mince. The single washing of mince did not improve the gel strength. The gel strength showed significant difference (p < 0.05) and decreased in single washed mince than its unwashed counterparts in catla and mrigal except rohu. It has been observed that gel did not set at pre-incubation temperature of 40 °C for 30 min treatment. SDS-PAGE patterns of proteins did not show any loss of myosin heavy chain (MHC) in single washed mince of Indian major carps. Texture profile analysis showed higher hardness in washed mince gel of Indian major carps while, non-significant difference (p > 0.05) was observed in cohesiveness, adhesiveness and elasticity properties. The whiteness index of washed mince showed improvement. The overall study indicated that mince gels can be made from unwashed mince of Indian major carps, alleviating the problems of waste water disposal leading to production of more value added products with better nutritional value.

Performance evaluation of a selective-enrichment-isolation protocol for Salmonella enterica from seafood.

In this study using 57 finfish samples of marine origin, selective enrichment in Rappaport-Vassiliadis (RV) broth followed by isolation on the Hektoen enteric agar (HEA) yielded 50 (53.2%) of 94 isolates. The results suggest RV-HEA as the most suitable media combination for the recovery of Salmonella from tropical seafood.

Characterization of chitin extracted from enzymatically deproteinized Acetes shell residue with varying degree of hydrolysis.

Acetes shrimp is an unexploited tiny shrimp mainly landed as bycatch which is a good source for the recovery of protein and chitin. In the present study, the residual shell obtained after the hydrolysis of Acetes was used for the extraction of chitin by combining enzymatic and chemical treatments. Enzymatic hydrolysis with Alcalase was performed at different rates. Results showed that the protein removal efficiency increases with the increase in DH and the maximum deproteinzation was achieved at 30 % DH (93.68 %). The FTIR spectra showed two sharp bands for chemically prepared chitin and 30 % DH chitin at 1627-1629 and 1664-1665 cm-1 indicating that its alpha amorphous structure. The degree of N-acetylation was found to be higher in enzymatically prepared chitin in all different hydrolytic treatment rather than chemically prepared. The surface morphologies of chitin revealed the porous and nanofibrous structures for 30 % DH chitin and chemically prepared chitin.

Effect of high pressure and setting condition on physico-chemical, structural and functional characteristics of transglutaminase mediated fish gels.

Application of High pressure and low temperature setting condition on microbial transglutaminase (MTGase) mediated gelation was studied against conventional cooking in pink perch mince. A high pressure of 250 MPa was given to pink perch mince samples added with and without MTGase enzyme, for a holding time of 12 min and a setting condition of 25 °C for 30 min was given prior and after the treatments. Nine random experiments (T1 to T9) were made against high pressure and cooking and analysed its textural and functional properties. Addition of MTGase and setting conditions had significant effect on the textural properties of the both samples especially in inducing the gel strength. Reduction in total and reactive sulfhydryl groups observed was due to the formation of disulfide linkages, which was found more in T6 to T9. Setting condition had significant effect on protein hydrophobicity in both pressure and heat induced gels. No significant variation in the Ca2+-ATPase enzyme activity was observed among treatments. SEM images revealed more closed and dense fibrous network in samples with enzyme (T6 to T9), due to more protein polymerisation. So MTGase enzyme along with pressure treatment enhanced the conformational stability and produce stronger networks through the formation of non sulfide bonds between proteins and setting reinforced these networks. Hence the synergistic effect of high pressure and MTGase can enhance the textural and functional properties of fish gels, when compared with the conventional cooking.

Effects of lysine and arginine on the properties of low-salt mince gel from striped catfish (Pangasianodon hypophthalmus).

Effects of basic amino acids, lysine (Lys) and arginine (Arg), at different levels (0%, 0.5%, and 1%, based on mince weight) on properties of striped catfish (Pangasianodon hypophthalmus) mince gel containing low salt (LS) and high salt (HS) were investigated. Without Lys or Arg addition, HS gel had the higher textural properties including hardness, chewiness, as well as cohesiveness than LS gel (P < 0.05) and the highest values were achieved when 1% Arg was incorporated in both LS and HS gels (P < 0.05). Arg had no effect on acceptability of mince gel. However, whiteness was decreased in HS gel when Arg was applied. Autolysis of gel was lower in HS gel containing Arg. No differences in protein patterns among all gel samples were found. Addition of Arg could increase the gelling ability of both LS and HS mince during heating as evidenced by higher storage modulus (G') and viscous modulus (G″). Mince gel added with Arg had orderly interconnected structure and their microstructure was finer than that without Arg. Therefore, Arg could be used in LS gel from striped catfish mince, in which quality of gel was equivalent to HS counterpart. PRACTICAL APPLICATION: Basic amino acid, especially arginine (Arg) with guanidinium group, could increase repulsive force between protein molecules at low-salt concentration (0.5%). This resulted in high solubilization of muscle proteins, whereas gel formation or gel strength was higher than that containing high salt (2.5% to 3.5%). Thus, Arg could be used for production of fish mince gel containing low salt with lowered health risk.

Evaluation of physicochemical and functional properties of spray-dried protein hydrolysate from non-penaeid shrimp (Acetes indicus).

BACKGROUND: Protein hydrolysate powder was prepared from non-penaeid shrimp (Acetes indicus) by enzymatic hydrolysis using Alcalase enzyme. Extraction conditions such as pH (6.5, 7.5 and 8.5), enzyme to substrate ratio (1.0, 1.5 and 2.0) and temperature (40, 50 and 60 °C) were optimized against the degree of hydrolysis using response surface methodology. RESULTS: Protein hydrolysate comprised of 740 g kg-1 protein, 150 g kg-1 ash and 90 g kg-1 fat contents. The amino acid score showed superior attributes with 56% essential amino acids. Furthermore, the functional properties of spray-dried protein hydrolysates were evaluated. Protein solubility was found to be the 90.20% at pH 2 and 96.92% at pH 12. Emulsifying properties were found to vary with the concentration of protein hydrolysates and the highest emulsifying capacity (26.67%) and emulsion stability (23.33%) were found at a concentration of 20 mg mL-1 . The highest and the lowest foaming capacity were observed at pH 6 and pH 10 with a concentration of 20 mg mL-1 . The water holding capacity of protein hydrolysate was found to increase with concentration, with a value of 5.4 mL g-1 at a concentration of 20 mg mL-1 . CONCLUSION: The results of the present study indicate that the use of A. indicus for the production of protein hydrolysate has good functional properties and nutritional value, rendering it suitable for broad industrial food applications. © 2019 Society of Chemical Industry.

Chitosan hydrogel inclusion in fish mince based emulsion sausages: Effect of gel interaction on functional and physicochemical qualities.

Chitosan has been reported to possess diverse applications in food industry. The cross linking properties of chitosan beneficially affects the protein-carbohydrate interactions which in turn enhances the functional properties in emulsion based meat products. In this context, the current study was conducted to incorporate hydrogel with different concentrations of chitosan (0%, 0.125%, 0.25%, 0.375% and 0.5%) into fish mince (Pangasianodon hypophthalmus) sausages in order to develop a functional sausage products with appealing flavour and desirable texture. The comparative analysis of various functional properties of the produced sausages showed that inclusion of chitosan gel had significant effect (p < 0.05) on the emulsion stability, gel-strength, pH, cooking yield, WHC, structural-compactness, texture, colour and sensory attributes of the products when compared with control. Further, from the study, it can be inferred that, sausages with 0.25% chitosan content (CS-2) uphold the best necessary functional and physiochemical attributes and presumed to be a superior ready-to eat product.

Antioxidant properties and instrumental quality characteristics of spray dried Pangasius visceral protein hydrolysate prepared by chemical and enzymatic methods.

Fish protein hydrolysates are digested form of protein with various bioactive properties where, the cleavages of molecular bonds of proteins can be broken by the enzymatic and chemical process. In this study, antioxidant properties of spray dried protein hydrolysate prepared from Pangasius viscera by using enzymatic (papain and pepsin), and chemical methods (hydrochloric acid and sodium hydroxide) were evaluated. Among the different treatments, pepsin-derived visceral protein hydrolysate showed the maximum antioxidant activity when used at higher concentrations. Essential amino acids (EAA) and hydrophobic amino acids are higher in papain-derived visceral protein hydrolysate. In pepsin-derived visceral protein hydrolysate, major proportion was contributed by glycine (Gly), glutamine (Glu), proline (Pro), and asparagine (Asp). Higher amount of aromatic amino acids are found in alkali-derived FVPH. Scanning electron microscopy (SEM) images of pepsin fish visceral protein hydrolysate showed better globular structure than the other treatments. It can be concluded that among the different treatments, the visceral protein hydrolysate prepared with pepsin had better overall quality regarding antioxidant properties and papain in nutritional point of view.

Fortification of extruded snacks with chitosan: Effects on techno functional and sensory quality.

Chitosan is a dietary fibre that possesses numerous functional, technological and physiological properties useful in improving food quality. Owing to its fat absorbing ability, chitosan is widely consumed as a health supplement in the form of tablets and capsules. With a view to enhance it consumption and availability, the current work was taken up to evaluate techno-functional quality improvement of shrimp based extruded snacks fortified with chitosan. Chitosan powder at 1, 2 and 3% (w/w) level was added to the base material (corn flour and rice flour in the ratio of 70:30 and 15% Acetes powder) for extrusion. Addition of chitosan in acetes based snacks significantly reduced expansion ratio, porosity and crispiness and increased the hardness value of the product. Chitosan addition had a significant effect (p > 0.05) on the moisture retention and total protein contents of the products as well. Thiobarbituric acid reactive substances (TBARS) value of chitosan fortified extrudate showed a significantly lower value than the control sample. A higher level of chitosan also resulted in colour reduction of the final product. The FTIR spectra of extrudate confirmed the stability of chitosan during extrusion conditions. The sensory score revealed that extrudate fortified with 1% chitosan was comparable to control sample. From this study it is concluded that 1% chitosan can be incorporated in Acetes based extruded snacks for an increased level of functionality.

Development of functional extruded snacks by utilizing paste shrimp (Acetes spp.): process optimization and quality evaluation.

BACKGROUND: Functional extruded snacks were prepared using paste shrimp powder (Acetes spp.), which is rich in protein. The process variables required for the preparation of extruded snacks was optimized using response surface methodology. Extrusion temperature (130-144 °C), level of Acetes powder (100-200 g kg-1 ) and feed moisture (140-200 g kg-1 ) were selected as design variables, and expansion ratio, porosity, hardness, crispness and thiobarbituric acid reactive substance value were taken as the response variables. RESULTS: Extrusion temperature significantly influenced all the response variables, while Acetes inclusion influenced all variables except porosity. Feed moisture content showed a significant quadratic effect on all responses and an interactive effect on expansion ratio and hardness. Shrimp powder incorporation increased the protein and mineral content of the final product. The extruded snack made with the combination of extrusion temperature 144.59 °C, feed moisture 178.5 g kg-1 and Acetes inclusion level 146.7 g kg-1 was found to be the best one based on sensory evaluation. CONCLUSION: The study suggests that use of Acetes species for the development of extruded snacks will serve as a means of utilization of Acetes as well as being a rich source of proteins for human consumption, which would otherwise remain unexploited as a by-catch. © 2017 Society of Chemical Industry.

Effect of processing conditions on degree of hydrolysis, ACE inhibition, and antioxidant activities of protein hydrolysate from Acetes indicus.

Protein hydrolysate was prepared from Acetes indicus which is a major bycatch among non-penaeid prawn landings of India. Hydrolysis conditions (enzyme to substrate ratio and time) for preparing protein hydrolysates using alcalase enzyme were optimized by response surface methodology using central composite design. The optimum conditions for enzyme-substrate ratio (mL/100 g) of 1.57, 1.69, 1.60, 1.56, and 1.50 and for hydrolysis time of 97.18, 96.5, 98.15 min, 102.48, and 88.44 min were established for attaining maximum yield, degree of hydrolysis, 2,2-diphenyl-1-picrylhydrazyl, angiotensin I-converting enzyme-inhibiting activity, and metal-chelating activity, respectively. ABTS radical scavenging activity and reducing power assay of optimized protein hydrolysate were found to be increased with the increase in concentration. The higher value of 7.04 (µM Trolox/g), 87.95, and 77.24%, respectively for DPPH, ACE, and metal-chelating activity indicated that the A. indicus protein hydrolysates have beneficial biological properties that could be well-utilized in the application of functional foods and nutraceuticals. Graphical abstract ᅟ.