Freshness Parameters of Scad (Decapterus Sp.) at the Arumbae Traditional Market in Ambon

Scad (Decapterus sp.) is a popular alternative to Rastrelliger sp. and Selaroides leptolepis and is typically sold from morning until evening. An investigation was conducted to determine the organoleptic and chemical parameters of fresh Scad sold in the market. Fresh Scad were sampled at 06:00 am (0 hours peddled), at midday (6 hours peddled), and at 06:00 pm (12 hours peddled). The fishes were sampled randomly and brought to the Fishery Product Technology Laboratory at the Faculty of Fishery and Marine Science, Pattimura University. Sensory and laboratory analyses were carried out covering organoleptic test, pH, and total volatile base (TVB). At 06.00 am, the organoleptic score was 9, pH was 5.7, and TVB was 15 mg/100g. At noon, the organoleptic score was 8, pH was 6, and TVB was 24 mg/100g, while at 6.00 pm, the organoleptic score was 6; pH was 6.8; TVB was 33.5 mg/100g. The findings concluded that the fresh Scad started deteriorating after 12 hours of peddling.


Introduction
Fish is a great source of nutrition, with high-quality protein and essential amino acids, as well as a wide variety of minerals, such as phosphorous, magnesium, iron, and iodine, found in marine fish.Fish is the richest source of polyunsaturated fatty acids such as eicosapentaenoic acid (C20:5, EPA) and docosahexaenoic acid (C22:6, DHA) also a good source of the B vitamin, A and D vitamins, especially in fatty species [1,2] Fish is highly perishable, it deteriorates rapidly due to the biological composition, as well as physical and chemical characteristics such as the combination of high-water activity (aw), neutral pH, low content of connective tissue and the presence of autolytic enzymes.Degradation occurs immediately after capture because of chemical and enzymatic reactions, followed by bacteria break down causing changes in appearance, texture, color and odor [3,4].
Scad (Decapterus sp.) is the most dominantly caught in Ambon, it is consistently available in the Arumbae traditional market throughout the year and is the most abundant among other types of small pelagic fish [5,6].It is a popular alternative to Rastrelliger sp. and Selaroides leptolepis and is typically sold from morning until evening.It is crucial to assess the freshness of the fish during the day to ensure fish quality in fulfills the nutrition requirements especially protein.Sensory, physical and chemical parameters indicate the fish's freshness.Some parameters including organoleptic score, pH and total volatile base (TVB) are appropriate to determine the freshness of raw fish [7,8].Based on that, this study aimed to determine the organoleptic score, acidity degree (pH) and total volatile base (TVB) which indicate the freshness of Scad sold in the Arumbae market.

Fish Sampling
Fish weight ranged between 89-165 grams and length between 20.5-24 were sampled from the Arumbae traditional market at 06:00 am, at midday, and 06:00 pm.Six sellers were randomly chosen to represent the three landing sites (Latuhalat village, Tulehu village and Hitu village) where the fish originated.The 1329 (2024) 012014 IOP Publishing doi:10.1088/1755-1315/1329/1/012014 2 fish were placed into Styrofoam boxes containing ice and then brought to the Fisheries Product Technology Laboratory at the Faculty of Fishery and Marine Science, Pattimura University.

Sensory and Chemical Parameters Tests
2.2.1.Organoleptic Test.The organoleptic test refers to SNI 2729:2013 [9], involves 20 untrained persons and organoleptic score determination using fresh fish scoring form covers fish appearance (eye, gill and surface body mucus), fish meat cutlet, fish smell and texture with the score range 1-9.Hyldig et al., 2010 [10].Twenty five grams of fish meat were blended with 30 ml distilled water and poured into a Beaker glass then, pH was measured using the Hana Model pH-meter.[11].Firstly, 2 gram of fish meat was homogenized with 10 ml trichloroacetic acid and filtered using the Whatman paper no.1.Secondly, as much as 1 ml homogenate sample was filled into the left site outer Conway chamber and 1 ml K2CO3 solution was filled into the right site.In the inner chamber 1 ml boric acid solution and 2 or 3 drops of Thasiro indicator were filled.The filtrate sample was mixed with K2CO3 solution to initiate the reaction, and then the Conway unit was closed and incubated at room temperature for 24 hours.Thirdly, the inner chamber titrated with N/70 HCL until the green color turns to pink color.

Result and Discussion
The organoleptic score of fresh Scad sold in the Arumbae traditional market can be seen on Figure 1.

Figure 1. Organoleptic Score of Fresh Scad
The fish was fresh on zero-hour peddling with the highest score appearance of eye, gill, surface body mucus, the meat cutlet, odor and meat texture.The eye is shiny with a curved eye-ball and clear cornea and pupil.Gill's color is dark red or reddish brown, bright with a very little transparent mucus.The surface body is shiny and bright with clear and transparent mucus layer.The meat cutlet has very bright and very substantial meat tissue.Scad odor is very fresh and the meat texture is dense, compact and elastic.The fish is fresh on 6-hours peddling with an 8 score on the appearance of the eye, gill, surface body mucus, the meat cutlet, odor and texture.The eye is slightly shiny with a flat ball and clear cornea and pupil.Gill's color dark red or reddish brown, less bright, with a little transparent mucus.The surface body is bright with a clear and transparent mucus layer.The meat cutlet has bright and firm meat tissue.Scad has fresh odour and the meat texture is dense, compact and elastic.
During the 12-hours peddling, the average organoleptic score appeared below 7. The eye was kind of shiny with a slightly concave eye ball and slightly cloudy cornea and a slightly grayish pupil.Gill's color is light red or light brown with cloudy mucus.Cloudy surface body mucus, is less bright and firm, the meat cutlet has a neutral odor, and the meat texture is soft and less elastic.
As the peddling time of fish increases, its overall organoleptic score decreases, indicating a decline freshness for up to 12 hours, with the score below 7 and the fish starting to deteriorate.The limit organoleptic score for fresh fish is 7 [9].Characteristic sensory changes occur in the appearance, odor, taste and texture of fish when it deteriorate.Chemical and enzymatic reactions, followed by bacteria break down causing appearance, texture and odor changes.Odor is one of the most important parameters used to evaluate fish freshness and the volatile compounds contributing to odor.Sensory evaluation is one of the most essential methods for assessing freshness and quality.Sensory methods perform correctly rapid and accurate tools provide unique information about food.It can be quickly performed, reliable, and nondestructive on new fish, and no expensive instruments are needed.Sensory evaluation give direct measurement of the perceived attributes and provide information assisting in a better understanding of consumer responses [10,11]

Figure 2. Chemical Parameters of Fresh Scad
The chemical parameters of fresh Scad sold in the Arumbae traditional market shown on Figure 2. The increases time of peddling, pH of the Scad increases as well as the increases of its total volatile base (TVB).The fish had excellent freshness with a pH 5.7 and TVB 15 mg/100 gr on zero-hour peddling and still in good freshness on 6-hours peddling with a pH 6.0 and TVB 24 mg/100 gr, while on the 12-hours peddling the Scad starting deteriorated with the pH 6.8 and TVB 33.5 mg/100 gr.
Fresh fish TVB content ranges from 5-10 mg/100g to 30 mg/100.A TVB of more than 30 mg/100 gr indicates that the fish is deteriorating [12,13].Those purchasing Scad on 12-hours peddling should be cautious of its freshness and quality limits, considering the TVB levels and the organoleptic score.Proper handling during the peddling of the fish is crucial for maintaining fish freshness.The pH escalation that occurs due to storage spoilage.At the beginning of storage, there was a slight decrease in pH, but it gradually increased.The initial pH decreases due to lactate accumulation, and the fish's release of post-protein proteolytic products increases the pH to alkalinity [14].The increase in TVB's value is caused by autolysis activity and putrevective bacteria keeping time on protein enzymatic process which changed to simple compounds, such as peptides, amino acids and ammonia.Furthermore, protein hydrolysis will lead to the formation of purine bases and pyrimidine [15].The process of protein degradation and its derivatives results in the production of volatile bases, such as ammonia, histamine, H2S, and trimetilamine, which have a foul smell [16].

Conclusion
The Scad maintains good freshness quality for more than 6 hours of peddling and starting deteriorated after 12 hours of peddling at the Arumbae traditional market in Ambon.Purchasing Scad on 12-hours peddling should be cautious of the limited freshness parametrs.