PROCESS DEVELOPMENT OF FISH SAUSAGE

Abstract

Process development for fish sausage from hybrid Clarias catfish meat and surimi was conducted using ratios of catfish meat to surimi at 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100; pork fat at 0, 5, 10, 15 and 20% (w/w of fish and surimi). Sensory evaluation scores showed that fish sausage prepared from fish meat to surimi at a ratio of 40:60 with 10% pork fat got the highest acceptability score. Improving of nutritive value by adding 0, 1, 2, 3, 4 and 5% fish oil or 0, 0.1, 0.3 and 0.5% calcium phosphate or calcium lactate (w/w of fish and surimi) was carried out. It was found that sausage sample with 3% fish oil or 0.5% calcium phosphate or calcium lactate was still accepted by the panelists.

INTRODUCTION

Production of emulsion sausage in Thailand has been recently expanded into commercial scale and consumption of such food in the country has increased due to its acceptable taste and high nutritional value. Most of sausages sold in the market were prepared from pork, chicken and beef. These types of emulsion sausage contained quite high fat content. According to the Thai food composition tables [1], the fat levels in Chinese style pork sausage, semi dried sausage, dried sausage and Vienna sausage were 31.4, 22.7, 40.7 and 24.8%, respectively. Fish is known to be high protein and low fat meat.

The present study is therefore designed to develop process of sausage production through replacing land animal meat with cheaper surimi and meat of hybrid Clarias catfish which is readily available in Thailand. Its main objectives were to (1) determine optimal ratios of surimi to fish meat and of pork fat to a mixture of surimi and fish meat in producing fish sausage and (2) compare sensory evaluation scores of sausage produced by the use of different concentrations of fish oil and calcium to improve nutritive value of the sausage.

MATERIALS AND METHODS

The materials used were hybrid Clarias catfish (female Clarias macrocephalus×male Clarias gariepinus); surimi (Quality Grade SSA); pork fat; fish oil (FRO-970923-2) from T.C. Union Agrotech Co., Bangkok; calcium phosphate prepared from tuna fish bone by the Department of Fishery Products, Kasetsart University; and calcium lactate (PURACAL PP/FCC) from Vicchi Consolitated Co., Bangkok.

Fish meat and surimi were each analyzed 2-3 for protein, lipid, ash, moisture and carbohydrate.

Optimal Ratios of Fish Meat to Surimi and of Pork Fat to Fish Meat and Surimi in Preparation of Sausage

Six samples were made by mixing fish meat and surimi at ratios (weight of fish meat to weight of surimi) of 100:0, 80:20, 60:40, 40:60, 20:80, 0:100. Each sample was thoroughly mixed in silent cutter (VEDEL-CUTTEX M11) to give acceptable characters with the other ingredients recommended by the Fishery Products Development Division [4], stuffed in 2.5 cm diameter cellophane casing, boiled at 80°C for 20 minutes and left until cool.

The samples were evaluated for sensory scores using a 9 point hedonic scale with score 1 for most unacceptable and 9 for most acceptable [5]. The sensory scores were given by 10–12 judges who were instructors, students and staff of the Department of Fishery Products, Kasetsart University. The scores were statistically analyzed using Banana Stat Pack Version 3.0, and Duncan's new multiple range test was employed for comparison among sample means [6].

The composition of the sausage sample with highest sensory scores was adjusted to give better preference characters by mixing fish meat and surimi with the other ingredients (unit in gram), as follows:

Table

Fish meat + surimi	100
Starch	5
Salt	3.5
Ground pepper	2
Ground garlic	1
Ground coriander	0.2
White egg yolk	2
Ice	20
Sugar	0.5
Monosodium glutamate	0.2

The mixture was divided into 5 samples. Each sample was added with pork fat at 0, 5, 10, 15 or 20% by weight of fish meat and surimi, thoroughly mixed, processed further as sausage and the sausage was evaluated for sensory scores in the same way as described earlier. To determine optimal amount of pork fat, sensory scores obtained among sample means were statistically analyzed and compared.

Optimal Concentrations of Fish Oil and Calcium in Improving Nutritive Value of Sausage

Fourteen samples were each made by mixing optimal ratios of fish meat to surimi and of pork fat to fish meat and surimi with adjusted other ingredients shown earlier. Six of them were each mixed with fish oil at 0, 1, 2, 3, 4, or 5% while each four of the remaining samples were each mixed with calcium phosphate at 0, 0.1, 0.3 or 0.5% and with calcium lactate at 0, 0.1, 0.3 or 0.5% by weight of fish meat and surimi. The samples were prepared as sausages, evaluated for sensory scores and analyzed for protein, lipid, ash, moisture and calcium. Sensory scores from all samples were statistically analyzed and compared to determine optimal concentrations of fish oil and calcium.

RESULTS AND DISCUSSION

Chemical Composition of Fish Meat and Surimi

The proximate composition of fish meat and surimi was shown in Table 1. The protein and lipid values found in surimi were slightly and much lower than those in fish meat. This is perhaps due to both protein and lipid were somewhat washed away during the preparation of surimi. Additions of cryoprotectant, sorbital and sugar in surimi production resulted in more carbohydrate found in surimi than in fish meat.

Table 1. Proximate Composition (%) of Fish Meat and Surimi

Composition	Fish Meat	Surimi
Protein	18.1	17.09
Lipid	4.4	0.04
Ash	1.0	0.56
Moisture	74.5	77.6
Carbohydrate	2.0	4.71

Preparation of Sausage

Table 2 shows sensory evaluation scores of sausage prepared using various ratios of fish meat to surimi. There was no significant difference in odour sensory scores. Sensory scores for colour, flavour, texture and overall preference were significantly different, with the highest scores for flavour, texture and overall preference obtained from sausage prepared using a ratio of fish meat to surimi at 40:60. It should therefore be noted that at this ratio surimi will greatly reduce cost of sausage production as it is much cheaper than fish meat.

Table 2. Sensory Evaluation Scores of Sausages with Various Ratios of Fish Meat to Surimi

	Sensory Evaluation Score
Fish Meat: to Surimi	Colour ^**	Odour ^ns	Flavour ^*	Texture ^**	Overall Preference ^**
0:100	7.40^a ± 0.92	6.63 ± 1.15	5.92^b ± 1.24	5.67^c ± 1.44	5.83^b ± 1.27
80:20	7.17^a ± 1.19	6.29 ± 1.05	6.96^a ± 0.75	6.79^ab ± 1.16	6.75^a ± 0.97
60:40	6.58^ab ± 1.31	6.42 ± 0.90	6.96^a ± 1.18	7.13^ab ± 1.00	7.04^a ± 0.86
40:60	6.00^bc ± 1.04	6.58 ± 1.31	7.33^a ± 0.89	7.33^a ± 1.07	7.29^a ± 1.01
20:80	7.42^a ± 0.90	6.13 ± 1.25	6.75^a ± 0.75	6.25^bc ± 1.42	6.58^ab ± 1.00
100:0	5.75^c ± 1.29	6.41 ± 1.51	7.17^a ± 1.34	6.67^ab ± 1.56	7.13^a ± 1.60

^ns Non-significant difference (P < 0.05).

^* Values followed by different letters in the same column are different at P < 0.05.

^** Values followed by different letters in the same column are different at P < 0.01.

Sensory evaluation scores of sausage prepared using the ratio of fish meat to surimi at 40:60 and then mixed with different concentrations of pork fat, fish oil and calcium were shown in Tables 3-4 and 5, respectively. Addition of pork fat or fish oil did not significantly affect sensory evaluation scores. However, the sausage added with 10% pork fat demonstrated highest scores for texture and overall preference, whereas that added with 3% fish oil gave superior acceptable scores than other higher concentrations and showed effective increment of its lipid value (Table 6). It was earlier reported [7] that added fish oil improved texture flexibility of sausage; but too high amount of fish oil may destroy fat-protein (myosin) emulsion, then reducing degrees of texture flexibility to a minimum.

Table 3. Sensory Evaluation Scores of Sausages with Various Concentrations of Pork Fat

	Sensory Evaluation Score ^ns
Pork Fat (%)	Colour	Odour	Flavour	Texture	Overall Preference
0	7.1	6.7	6.9	7.2	7.0
5	6.9	6.6	7.1	7.1	7.3
10	7.0	6.6	7.0	7.5	7.3
15	7.1	6.9	6.9	7.3	7.0
20	6.9	6.6	6.6	7.3	6.9

^ns Non-significant difference (P < 0.05).

Table 4. Sensory Evaluation Scores of Sausages with Various Concentrations of Fish Oil

	Sensory Evaluation Score ^ns
Fish Oil (%)	Colour	Odour	Flavour	Texture	Overall Preference
0	7.4	7.1	7.3	7.6	7.3
1	7.4	7.1	7.3	7.5	7.3
2	7.3	7.0	7.0	7.5	6.8
3	7.2	7.4	6.7	7.4	6.6
4	6.8	6.6	6.0	6.8	6.4
5	6.8	6.1	6.1	6.9	6.1

^ns Non-significant difference (P < 0.05).

Table 5. Sensory Evaluation Scores of Sausages with Various Concentrations of Phosphate and Lactate

		Sensory Evaluation Score
		Lactate (%)			Phosphate (%)
Character	Control	0.1	0.3	0.5	0.1	0.3	0.5
Colour ^ns	6.50 ± 0.59	6.50 ± 0.54	6.50 ± 0.72	6.50 ± 0.52	6.50 ± 0.42	6.50 ± 0.42	6.50 ± 0.44
Odour ^ns	6.80 ± 0.76	6.40 ± 0.77	6.70 ± 0.98	6.50 ± 0.65	6.40 ± 0.38	6.00 ± 0.68	6.50 ± 0.61
Flavour ^*	7.10 ± 0.71^a	6.50 ± 0.52^b	6.53 ± 0.81^b	6.20 ± 0.72^b	6.30 ± 0.71^b	6.15 ± 0.87^b	6.30 ± 0.57^b
Texture ^**	7.10 ± 0.63^a	5.50 ± 0.55^c	5.30 ± 0.48^c	5.60 ± 0.67^c	6.10 ± 0.62^b	6.15 ± 0.87^b	6.30 ± 0.57^b
Overall preference ^**	7.10 ± 0.59^a	5.75 ± 0.69^cd	5.65 ± 0.78^d	5.80 ± 0.52^cd	6.25 ± 0.55^b	6.15 ± 0.72^bc	6.30 ± 0.48^b

^ns Non-significant difference (P < 0.05).

^* Values followed by different letters in the same row are different at P < 0.05.

^** Values followed by different letters in the same row are different at P < 0.01.

Sausages added with different concentrations of calcium lactate or calcium phosphate gave similar acceptable sensory evaluation scores for colour, odour and flavour. Sensory evaluation scores for texture and overall preference of sausages added with lactate were significantly lower than those added with phosphate at all concentrations. The highest scores for overall preference were obtained from adding lactate or phosphate at 0.5%. Though adding of calcium at 0.5% demonstrated acceptably low sensory scores, but it increased calcium in sausage to a satisfactory level (Table 6) as compared to that in the sausage added no calcium or even in fish meat.

Table 6. Proximate Composition of Sausages with and without Fish Oil and Calcium

Composition (%)	Without Fish Oil and Calcium	With 3% Fish Oil	With 0.5% Calcium Phosphate
Protein	13.73	13.67	13.91
Lipid	3.16	4.5	3.70
Ash	2.50	2.65	2.82
Moisture	74.50	75.11	73.5
Calcium	0.041	0.030	0.303

Acknowledgments