Yield
The average length and weight of lizard fish used in the present study were 28.91 cm and 198.81g respectively and found to be suitable as raw material for the preparation of imitated shrimp products. The average dressing, minced meat and yield of surimi obtained during the processing of
S. tumbil were presented in Table 1. The yield of dressed fish in the present study was 77.64%. (Sharma, 1989) was found 76% of meat recovery from lizard fish through mechanical separation and
(Joseph et al., 1980) in lizard fish obtained a dressing yield of 50%. Dora, (1992) has reported 60 and 66% of yield in
Johnius sp and
Nemipterus japonicus respectively.
Revenkar et al., (1981) acquired the dressing yield of 50 - 52% and 34 - 50% respectively in croaker and pink perch.
Hema et al., (2012) reported that the dressing yield of short nosed white tripod fish was 47.43%. In general, dressed yield was directly proportional to the size of the fish. The fairly high yield obtained in the present study might be due to the comparatively bigger size of the fish used and careful handling during dressing.
Currently, deskining and deboning processes were carried out by machines that removed the muscle portion from the frames which includes skin, scales, fins and bones of fish. The average yield of minced meat was 56.19% in terms of minced meat from whole fish. The minced meat or deboned meat yields obtained from different fish have also varied considerably with species. Minced meat yields of Pacific hake and cod were 40 and 45% respectively
(Crawford et al., 1972); in terms of dressed weight. According to
Gopakumar et al., (1992), the yield of different types of tropical marine fishes processed by Baader 694 deboning machine was in the range of 32 to 54%. Lin and Morrisey, (1995) reported 27% of minced meat in Squawfish. The yields of minced meat from various fishes of Indian waters such as
Tachysurus spp. (27%),
Megalopsis cordyla (31%),
Johnius sp. (34%),
Uppinus vittatus (46%),
S. tumbil (56%) and
Trichurus savala (53%) are reported by
Muraleedharan et al., (1996), lizard fish was 42.22%
(Jitesh et al., 2011). Hema et al., (2012) reported minced meat yield obtained from white tripod fish was 26.11%. Rathnakumar and Pancharaja, (2018) reported 50% yield of minced meat was possible from whole fish. Compared to these results, the minced meat yield of lizard fish from the present study was higher (56.19%) in terms of total weight that could be due to the efficient deboning operation performed through improved machineries.
In the present study, the yield of surimi obtained was 32.89%. The average yield of haddock was 26.7%
(Hastings et al., 1989). The yield of surimi from various fishes of Indian waters was in the range of 23-32%
(Muraleedharan et al., 1996; Muraleedharan et al., 1997) and lower yield of 17% was reported in Northern Squaw fish (Lin and Morrisey, 1995). Kaba, (2006) reported that the yield of anchovy was 22%. Dey and Dora, (2011) reported 32.90% yield of gangetic croaker surimi. In the present study, the yield of surimi value was comparable with the value reported by Dey and Dora, (2011) in gangetic croaker (32.90%). Although the surimi yield percentage in the present study was slightly higher than the yield rate as reported by Sharma, (1989).
Proximate composition of minced meat
Proximate composition of the minced meat, in terms of wet weight for lizard fish (
Saurida tumbil) was 80.5% moisture, 15.98% protein, 1.20% fat, 1.40% ash and 1.60% carbohydrate given in Table 2. According to Love, (1980), proximate composition of fish varies with age, sex, size, season, feed availability, species, place, type of muscle, time of spawning and environmental factors. Kongpun, (1999) reported that lizard fish had a protein content of 17.65% and moisture content of 79.03%, the fat content was 1.07%.
Suwansakornkul et al., (1993) reported even lower level of fat contents in
S. undosquamis,
S. wanieso and
S. elongate which was less than 1%.
Jitesh et al., (2011) analysed that the proximate composition of lizard fish (
Saurida tumbil) had 78.43% of moisture content, 17.15% of protein content, 1.89% of lipid and 1.59% of ash content.
Meena et al., (2015) has reported that the proximate composition of
Saurida tumbil contained 76.87% of moisture, 19.34% of protein, 1.29% of fat and 1.83% of ash. Rathnakumar and Pancharaja, (2018) reported that the proximate composition of lizard fish minced meat has 76.99% of moisture, 19.01% of protein, 1.13% of fat and 1.31% of ash. Similar results were reported by many researchers
(Numakura et al., 1989; Rathnakumar and Shamasundar, 1998). The present value was concomitant with value of Rathnakumar and Shamasundar, (1998) and
Palanikumar et al., (2014). Researchers have detailed on the proximate composition and nutritive profile of lizard fish
(Chattopadhyay et al., 2004). Palanikumar et al., (2014) studied the proximate composition of minced meat of lizard fish that contains 79.19% of moisture, 16.28% of protein, 0.29% of fat, 1.85% of ash and 0.09% of carbohydrate.
Proximate composition of surimi
Surimi of lizard fish (
Saurida tumbil) had 83% of moisture, 13.85% of protein, 0.86% of fat and 0.8% of ash Table 2. The fat and protein contents of surimi were less when compared to minced meat because the fat content would be removed during the washing process Roussel and Cheftel, (1990) have assessed the quality of surimi produced out of Atlantic sardine by adding 4% sugar and 4% sorbitol as preservatives and stored at - 45°C for 8 months and revealed the moisture, protein and fat contents were 76%, 14% and 1% respectively at the end of the storage period. Washing helps to remove the pigments, blood, odour, enzymes, mucus and some water soluble proteins.
The protein content of surimi was higher than the minced meat in terms of dry weight due to the different washing steps. The present yield of surimi protein value was in concomitant with the values (79.5%) of
Gopakumar et al., (1992). According to
Suvanichi et al., (2000) surimi has lower levels of fat and ash content and increased moisture content than the unwashed minced meat. USDA, (2010) has reported that the standards for proximate composition of surimi was 76.3% moisture, 15.3% protein, 0.9% fat and 0.7% ash on wet weight basis.
Huda et al., (2012) reported that moisture and protein contents of surimi made from threadfin bream were 81.31% and 16.04%, respectively.
The proximate composition of fish meat indicates that the fish used was lean. The proximate composition of fish meat before and after water washing showed a significant leap of moisture content from 80.5 ± 0.20% to 83 ± 0.50%, significant reduction in protein (15.98 ± 0.06 to 13.85 ± 0.09%), fat (1.2 ± 0.20% to 0.86± 0.00%) and ash (1.4 ± 0.02% to 0.8% ± 0.02%) contents. The reduction of protein was due to loss of water soluble proteins, removal of water soluble mineral caused the decrease in ash content (Sijo
et al., 2002) and an increase in moisture content was owing to the hydration process of myofibrillar proteins
(Suvanich et al., 2000). A good quality surimi should contain low fat content.
Biochemical changes
In the present study, biochemical changes of lizard fish minced meat and surimi such as free fatty acid, peroxide value and pH values are shown in Table 2. Lizard fish minced meat contained free fatty acid (0.5%), peroxide value (0.8 miilli. eq O
2/ kg), TBA (0.14µM/g), pH (7.02) and lizard fish surimi had free fatty acid (0.98%), peroxide value (1.2 miilli. eq O
2/ kg), TBA (0.3µM/g) and pH 7.02.
Jitesh et al., (2011) reported that TVB value of lizard fish was 12.13mg/100g. In the present study, test values of free fatty acid, peroxide value (PV) and TBA in minced meat and surimi were found to be within the limit of with no mark of any rancidity.
Designing of aluminium and polylactic acid shrimp mould
In the present study, designed the aluminium shrimp moulds such as individual shrimp mould and combined shrimp moulds (nine shrimp moulds) (Fig 1) processed by Unigraphics and Mastercam softwares is completed modeling and design applied reverse engineering technique as shown as Fig 1 and Fig 2. These softwares establish like shrimp model using contour tool path can make die cavity surface smooth, achieving realistic appearance and smooth surface.
Wei et al., (2010) obtained through scanning of shrimp (boiled, head and shell removed) point cloud data which is processed by CATIA V5 R16 and then completed modeling and design applied reverse engineering technique. Ping (1997) reported that the geometric properties of the curved surface, it is processed with milling cutter of 5 mm diameter with tolerance for 0.02 mm. According to precision requirements, through ISO-scallop method, all the knife contacts are gained, further calculating the corresponding points. So the cutter path is derived, which is made up of discrete cutter locations on the whole surface. Longhan (2004) reported that simulation renderings in the cavity surfaces using NURBS, which have very good smoothness. Finally conclude that, the contour tool path can make mould surface smooth and realistic appearance of the shrimp model.
Proximate composition of Ready to eat Analogue Shrimp Product
Proximate composition of the ready to eat analogue shrimp product, in terms of wet weight basis for lizard fish (
Sauridatumbil) represents 87% moisture, 10.15% protein, 0.04% fat, 0.80% ash and 2.50% carbohydrate respectively provided in Table 2. However, no one reported the ready to eat analogue shrimp products from lizard fish (
Saurida tumbil).