The optimum formulation for mutton-based meatballs from the past experiment was further tested by the laboratory panel and by a small Thai consu mer panel. The proportion of mutton lean was increased in the formulation in order to investigate whether meatballs with a higher content of mutton were acceptable to the Thai consumers.
7.5. 1 Methods
This experiment was to study not only the acceptability by a laboratory panel but also the degre e of liking and willingness of purchasing by a small household consumer panel of meatballs made with the predetermined optimum proportion of mutton (75%) . In addition, . two other proportions of mutton at 95% and 1 00% were concurrently tested to determine whether these new mixes yielded products with desirable attributes especially aroma and flavour and were acceptable to the Thai consumers. The proportions of meats and fat u sed are given in Table 7. 1 1 .
Table 7.1 1 Percentages of meats and fat used in meatballs Treatment 1 2 3 Mutton Lean(%) 75 95 1 00 Pork Lean(%) 20 o o Pork Fat (%) 5 5 o
The meatballs were made according to materials and methods described in Chapter 4 (Sections 4.1 . 1 and 4.1 .2 respectively) . Untrimmed boneless mutton leg was u s ed as mutton raw materi al. The meatballs were made , for e ach treat m e nt, u sing v a rious proportions of meats and fat as shown above but with the same contents of six ingredients; 4% tapioca starch, 2.5% salt, 0.25% STPP, 0.75% white pepper, 0.8% garlic and 0.6% onion, as selected in the last experiment.
The meatballs were tested by two types of sensory evaluation panel ; a laborato ry panel comprising the eight experie nced Thai pane lists and a household cons u m e r panel comprising seventeen Thais who were stude nts or working people and resided in the Palmerston North area.
For the laboratory panel, the meatballs were prepared for serving by deep frying in soybean oil at 200 ± 5 Co for 2 minutes or by cooking in boiling water (1 00 CO) for 2 minutes in order to dete rmine whether different methods of cooking resulted in any difference in attribute acceptability. The questionnaire used for sensory evaluation was the same as the o n e used for the last experiment; Section 7.4.1 (see Appendix 7.3) .
For the household consu mer panel, the samples from each formu lation were distributed, together with questionnaires, to 1 7 Thai consumers. In each questionnaire (see Appendix 7.4) , a 7-point hedonic scale was provided. The categories used to describe the degree of liking were the ones used by Winger ( 1 984) . i.e. with bottom and top scores described as could not be worse - cou ld not be bette r. The panelists were asked to ass e s s the appearance, aroma, texture, flavour and overall liking. Moreover, willingness to purc hase each meatball sample was asked. The categories used for this question we re t h e ones used by Moskowitz (1 983), i.e. definitely would not buy - definitely would buy.
The data obtained from the laborato ry panel and the household consumer panel were subjected to analysis of variance as described in Chapter 4 (Section 4.3). The scores obtained for 'willingness of purchasing' were grouped in each category and the percentage based on the numbers of respondents who expressed their willingness to purchase for that category was calculated.
7.5.2 Panel Results
The mean ideal ratio scores of sensory attribute acceptability for meatballs are presented in Table 7 . 1 2.
Table 7. 1 2 Mean ideal ratio scores for sensory attribute acceptability of meatballs tested by the laboratory panel ( 1 )
Method of Attribute Treatment(2)
Cooking 1 2 3
Deep frying Aroma 0.87 0.81 0.81
(0.02) (0.04) (0.04) Texture 0.87 0.83 0.79 (0.02) (0.03) (0.03) Flavour 0.86 0.80 0.86 (0.03) (0.03) (0.03) Overall 0.89 0.80 0 .83 (0.01 ) (0.03) ( 0 . 03) Boiling Aroma 0.8 1 0.75 0.79 (0.04) (0.05) (0.04) Texture 0.76 0.76 0 .85 (0.04) (0.05) ( 0 . 03) Flavour 0.85 0.82 0 .80 (0.03) (0.04) (0.03) Overall 0.83 0.80 0.80 (0.03) (0.04) (0.03)
(1 ) All the mean values for e ach attribute acceptability in the same row w e re not
significantly different (p � 0.05).
Numbers in parentheses are standard errors of the means of the ratio scores a mo ng the eight pane lists.
It was shown that meatballs made with various proportions of mutton lean, pork lean and pork fat were not significantly different (p � 0.05) from each other in acceptability of each sensory attribute. This was true whether the meatballs were prepared for serving e ither by deep-frying or boiling. Meatballs made with pork lean (treatment 1 ) had higher ideal ratio scores in most attributes especially for aroma, flavour and overall acceptability than those without pork lean (treatments 2 and 3). This was likely due to the reason that pork reduced the extent of muttoniness in the products thus resulting in higher panelists' ratings for these attributes.
Deep frying slightly improved the overall acceptability of meatballs over boiling. I n general, meatballs prepared for serving by deep frying received higher scores for all attributes but particularly texture than those prepared by boiling . Deep f rying might be a suitable m ethod for preparation of meatballs for consumption since cooking oil might add a little palatability to the products.
7.5.3 Household Consumer Panel Results
The mean scores for liking of sensory attributes of meatballs by hedonic scaling are g iven in Table 7. 1 3.
Table. 7. 1 3 Mean hedonic scores for liking of sensory attributes o f meatballs tested by a household consumer panel ( 1 )
Treatment (2) 1 2 3 Liking of appearance 4.76 4.82 5.00 (0.25) (0.29) (0.24) Liking of aroma 4.29 3 .65 4.41 (0.35) (0 .31 ) (0.3 1 ) Liking of texture 4.88 4. 1 8 4.76 (0. 1 9) (0.31 ) (0.25) Liking of flavour 4.59 4.1 2 4 . 53 (0.31 ) (0.28) (0.23) Overall liking 4.47 3 .82 4.35 (0.29) (0 .3 1 ) (0.23)
( 1 ) All the mean scores for each attribute in the same row were not significantly d ifferent (p � 0.05). Numbers in parentheses are standard errors of the means among the seventeen consumers . The hedonic scale was from 1 -could not be worse to 7 -
could not be better.
It was likely, although not significantly different (p � 0.05), that meatballs made with pork lean (treatment 1 ) were regarded as better in texture, flavour and overall liking than those without pork (treatments 2 and 3). Treatment 1 received ratings of liking between 4 (neither like nor dislike) and 5 ( like moderately) as did treatment with 1 00% mutton. Treatm e nt 3 with 1 00% mutton received higher ratings in appearance and aroma than treatment 1 .
The mean scores given by the six consumers, who had also participated in a laboratory panel, were calculated. It was interesting to note that mean scores for almost all liking attributes were in favour of treatment 1 ; i.e. the highest mean scores in liking of appearance, t exture, flavour and overall liking among the three treatments. However, only the mean score for liking of aroma equalled that of treatment 3 .
T h e numbers and percentages of the pane lists who gave their willingness o f purchasing meatballs are given in Table 7.1 4.
Table 7. 1 4 Numbers and percentages of the consumers who expressed their willin gness to purchase meatballs in a household consumer panel
Treatment ( 1 )
Category 1 2 3
No.(%} No.(%} No.{%}
Definitely would buy Probably would buy Might or might not buy Probably would not buy Definitely would not buy TOTAL 1 6 5 2 3 1 7 {6} 0 (35) 4 (29) 5 ( 1 2) 2 ( 1 8) 6 (1 00) 1 7 (0) 1 (24) 5 (29) 5 ( 1 2) 6 (35) 0 ( 1 00) 1 7
( 1 ) Refer to Table 7. 1 1 for percentages of meats and fat used for each treatment.
{6} ( 29) (29) (35) (O) (99)
There were 41 %, 24% and 35% of the respondents who expressed their willingness 'to buy' and 30%, 47% and 35% of the respondents who expressed their willingness 'not to buy' the meatballs in treatments 1 , 2 and 3 respectively. Therefore , treatment 1 , although not substantially diffe re nt, was preferred in terms of willingness of pu rchasing to other treatments.
There were co mments by some participants in the household cons u m e r pan e l that meatballs, especially those made with higher percentages of mutton, still had muttony flavour. Nevert heless, there were a few participants who stated that meatballs fro m treatment 1 (with 75% mutton l e a n , 20% pork lean a n d 5% pork fat ) , afte r f u rthe r development, would be accepted by the Thai consumers.
Most pane lists suggested that meatballs could also be cooked by boiling in stock and eaten with noodles or by roasting or charcoaling and eaten with some sauces, e.g. sweet and sour chilli sauce. A few panelists suggested meatballs be cooked with curry or chilli past e . Also, a suggestion was made that ginger could possibly help to conceal strong odour and flavour of mutton.
7.5.4 Correlation of and Household Consumer Panel Results
The means of the scores for e ach sensory attribute acceptability from all treatments i n the laboratory panel were correlated with the means of liking scores for each attribute f ro m all treatments in the hou sehold consumer panel. It was found that flavou r acceptability (lab panel) significantly correlated (0. 1 � P > 0.05) with liking of aroma (consumer pane l) and also significantly correlated (0.1 � P > 0.05) with liking of flavo u r. Moskowitz ( 1 985) indicated that the liking ratings assigned by the home use panel correlated fairly w e ll with the liking ratings assigned by the research guidance panel.
7.5.5 Fat Contents of the Meatballs
The fat contents of the meatballs from treatments 1 , 2 and 3 were 8.8%, 1 0.7% and 7.1 % respectively. Therefore, it was suggested that fat content of meatballs be kept at a level not exceeding 1 0%. A number of researche rs reco m mended that mutton fat co ntent in processed meat products be at a level not exceeding 1 0% (refer to Chapter 5). In addition, this level seemed to be justifiable since commercial meatballs ( made from very lean meat) in Thailand have approximately 3-4% fat.
7.5.6 Discussion and Conclusion
The resu lts of both the laboratory panel and the household consumer panel showed that mutton-based meatballs were not perfectly accepted or liked by the Thais. The ideal ratio scores for sensory attribute acceptability given by the laboratory panelists were relatively high, i.e. greater than 0 .85 for deep-fried samples of treatment 1 . This might be due to the reason that the labo ratory panelists were more experienced and they were already acquainted with tasting mutton-based meatballs, so they were quite satisfied with s ensory attributes they assessed. However, consumer degree of liking for sensory characteristics of the same meatball samples were not really high, i.e. the hedonic scores were 4.29 - 4.88 for treatment 1 and 4.35 - 5.00 for treatment 3. These score intervals were still relatively low for the 7-point hedonic scale. Most participants in this household consumer panel were not experienced and were not acquainted with tasting mutton-based meatballs, therefore they still d id not really like the m thus resulting in their 'not hig h' ratings fo r m e atballs' characteristics.
In general, the results obtained in both the laboratory panel and the household consu mer panel supported selection of treatment 1 , with 75% mutton lean, 20% pork lean, 5% pork fat as a suitable formulation for further development. Treatment 3, with 1 00% mutton lean, was another suitable candidate in view of exploiting mutton as a raw material.
However, when considering that the meatballs were developed for the consumers in Thailand who are not familiar with mutton f lavour and aroma at all , it was expected that the lower the percentage of mutton the more acceptable the product.
7.6 F L AV O U R I M P R O V E M E N T O F T H E O P T I M U M FO R M U LAT I O N A N D