R ESEARCH ARTICLE ScienceAsia 26 (2000) : 219-224

Production of Meat-Like Flavor

Saiyavit Varavinita,*, Sujin Shobsngobb, Mate Bhidyachakorawata and Manop
Suphantharikaa
a
Department of Biotechnology, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok
10400, Thailand
b
Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400,
Thailand.
* Corresponding author, E-mail: scsva@mucc.mahidol.ac.th

Received 27 Apr 2000

Accepted 24 Nov 2000

ABSTRACT Meat-like flavors, prepared by digestion of cooked meats by protease, followed by refluxing
the mixture of meat hydrolysates, yeast extract, cysteine or methionine and glucose to obtain meat-like
flavors. The sensory evaluation data for beef flavors compared to commercial beef (CB) flavor showed
that the prepared flavor BH10YE was the best, among BH-R and BH20YE, and significantly different
from CB (P≤0.05). The prepared pork flavors, PH10YE, PH20YE and PH-R, exhibited higher sensory
scores than that of commercial pork flavor (CP) (P≤0.05) in which PH10YE was found to be more
accepted than PH20YE. However, the prepared chicken flavors ,CH10YE and CH20YE, were not
significantly different from commercial chicken flavor (CC) (P>0.05).

KEYWORDS: meat flavor, beef flavor, chicken flavor, pork flavor, yeast extract.

INTRODUCTION bis-(2-methyl-3-furyl) disulphide. 8 The major

pathway for pork flavor development is from the
The precursors of meat flavor can be divided into degradation of lipids 9 and the free fatty acids are
two catagories as water soluble components (amino released during the process. The lipid degradation
acids, peptides, carbohydrates, nucleotides, thiamines, products are found to be saturated and unsaturated
etc.) and lipid or water insoluble components. The hydrocarbons, β-keto acids, methyl ketones, lactones
Maillard reaction between amino acids and reducing and esters.9 The Maillard reaction between reducing
sugars leads to aroma. The meat flavor precursors sugars and amino acids, peptides or proteins also
obtained by heating meat lead to meat flavor via the leads to pork flavor. The Maillard reaction between
Maillard reaction.1 The flavor precursors have been cysteine and reducing sugars is especially important
identified to be free sugars, sugar phosphates, in yielding pork like aroma.10 Other reactions such as
nucleotides, free amino acids, peptides, thiamine and the interaction of the Maillard reaction with lipids,11
other compounds. The reaction of cysteine and sugar and the degradation of thiamine can also generate
can lead to characteristic meat flavor especially for many sulphur-containing pork flavor compounds.12
chicken and pork.2 Meat flavors can be prepared by The flavor of chicken was studied by Gasser and
the pyrolysis of amino acids and peptides, carameli- Grosch13 who identified 2-methyl-3-furanthiol, 2-
zation of carbohydrate, degradation of nucleotides furfurylthiol, methionol, 2,4,5-trimethyl-thiazole,
and thiamine or thermal degradation of lipids.3 nonanol, 2-trans-nonenal, and other compounds as
The flavor of beef results from lipid oxidation important. Volatile compounds generated from the
and/or degradation4, thermal degradation and inter- Maillard reaction and lipid oxidation are obviously
reaction of proteins, peptides, amino acid, sugars and major sources of chicken flavor.14 The compound,
nucleotides, and thermal degradation of thiamine. 2-methyl-3-furanthiol, is the most important
These reactions produce many important beef aroma compound in chicken flavor. It results from the
components.5 Maarse and Visscher have classified reaction between ribose and sulphur containing
some 880 aroma components from cook beef6 and amino acids such as cysteine or cystine.15
found that 25 of them possessed a meaty odor. The flavor industry has developed a range of
The flavors of pork have been found to be hydro- imitation flavors or meat-like flavors, although the
carbons, alcohols, carbonyls, carboxylic acids, esters, specific flavor profile of a targeted meat item (eg,
lactones, ethers, sulphur containing compounds and roast beef) has proven much more difficult to
heterocyclic compounds.7 The pork flavor precursors achieve. A great majority of patents dealing with the
are generally derived from 2-methyl-3-fyranthiol and production of meat flavors are based on the Maillard
220 ScienceAsia 26 (2000)

type reactions. Many desirable meat like flavor precursors derived from enzymatic hydrolysis of
volatiles are synthesized by heating water-soluble beef, pork or chicken. The aroma reaction between
precursors such as amino acids and carbohydrates.16 yeast extract and meat hydrolysates in the presence
It is generally agreed that sulfur compounds, of cysteine or methionine and glucose is also
particularly cysteine play a key role in the develop- discussed.
ment of meat like flavors. In 1960, Morton et al.17
received the first patent which claimed that heating MATERIALS AND METHODS
cysteine with ribose, glucose or xylose gave a flavor
and aroma reminiscent of meat. Many of the patents Meat of chicken, beef and pork was purchased
that followed immediately thereafter chose cysteine from the supermarket. Spent Brewer’s yeast was
as their preferred amino acid for the development of obtained from Boonrawd Brewery Co.Ltd, Thailand.
meat flavor. It served as an acceptable substrate for Papain was supplied by Sigma Chemical Co, USA.
the formation of a large number of sulfur containing Commercial yeast extract, roasted chicken taste (CC)
flavor chemicals associated with the meaty aroma. and roasted beef taste (CB) were obtained from
Several other patents stress the importance of import companies while pork extract flavor was
cysteine/cystine as precursors for the development kindly donated by a flavor company in Thailand. L-
of meat flavor.18-23 Methionine was obtained from Fluka, Switzerland.
Meat hydrolysates or meat extracts have served L-Cysteine hydrochloride monohydrate, D-Glucose
as condiments which can impart the same flavor as monohydrate, sodium hydroxide, and hydrochloric
the meat stock from which they were derived. acid were supplied by Merck Co Ltd, Germany. IMP
However, it is known that meat extracts do impart and GMP were kindly donated by Ajinomoto Co.
poor flavor and odor characteristics and these Ltd, Thailand.
products are also expensive.
There have been several patents that involve the Proximal analysis of the meat flavors BH10YE,
addition of crude protein hydrolysates. Apart from PH10YE and CH10YE
their role as amino acid precursors, they may also Protein content was determined by the Kjeldahl
act as a source of reducing sugars or other carbonyl method. Fat, ash and moisture contents were
compounds thereby serving as reactants for the analyzed according to procedure described in the
Maillard reaction. The best known protein AOAC manual.
hydrolysates universally accepted for their useful
function for flavor are HVP and yeast extract. Several Preparation of yeast extract
early patents have made use of yeast extracts or yeast Spent brewer’s yeast with solid content of about
hydrolysates as one of the reactants for the thermal 18-20% (w/w) was adjusted to pH5.0 by addition of
generation of meat flavorings.24-27 either 1M HCl or 1M NaOH. It was then autolyzed
Meat-like flavors are known to make a significant at 50°C for 24 h. The autolyzed solution was heated
improvement in many savory foods such as soups, at 85°C for 10 min to deactivate the enzyme, and
gravies, snacks and in a variety of other prepared then it was centrifuged at 4500 rpm for 10 min.28-30
foods. Almost all these food types can be purchased The clear supernatant was referred as yeast extract
in a final cooked form so that it requires only heating. with 7-8% (w/w) of solid content, which was then
It should be noted that, although meat like flavors concentrated in rotary evaporator to 30% (w/w) solid
developed so far are reasonably satisfactory, they are content.
still far from real meat flavors. These products do
not yet have the unique characteristic flavor profile, Removing of bitterness and beer flavor from yeast
the meat component of beef, chicken or pork has, extract
which in general are clearly distinguishable from The bitter compounds and beer flavor in yeast
each other, organoleptically. extract solution prepared from spent brewer’s yeast
Thailand has to import large quantity of food was removed by adding activated carbon (about 3.5g
flavors annually. If these food flavors can be produced carbon to 100 ml of yeast extract solution) and stirring
in Thailand, it not only reduces the importation of at 50°C for 1 h. The activated carbon was then
food flavors but it can also be able to export to other removed by centrifugation at 4500 rpm for 10 min.
countries.
In this study, the formation of beef, pork and Preparation of meat hydrolysate
chicken flavor and aroma was examined using The meat (chicken, pork or beef), which was
ScienceAsia 26 (2000) 221

free of fat, was cut into small pieces and boiled for staffs, undergraduate and graduate students at
10 min. The cooked meat was ground and water was Biotechnology Department, Faculty of Science,
added to obtain 25% (w/w) of solid. Papain was then Mahidol University.
added to the ground meat slurry at 0.5% (w/w) of The flavors were served in the form of a soup
the dried meat followed by incubation at 60°C for consisting of 1.5% (w/v) flavor, 0.75% (w/v) salt and
12 h. The enzyme was then deactivated at 90°C for 0.25% (w/v) of flavor enhancers. The flavor
15 min.31,32 The meat hydrolysate slurry was then enhancers were MSG, IMP and GMP in the quantity
clarified by centrifugation at 10500 rpm for 15 min. ratio of 98:1:1, respectively. For evaluation, panelists
The clear supernatant was transferred to a separatory were asked to smell and taste the odor and flavor of
funnel and any surface oil removed. The resulting these products. They were asked whether the odor
solution was called meat hydrolysate. and flavor of the presented soups (from prepared
and commercial meat flavors) were similar to those
Preparation of flavor from refluxed meat of specific meat products. A 9-point scale was used
hydrolysate for evaluating these flavors with 9 = most like the
The meat hydrolysate was adjusted to pH 6.0 and designated meat and 1 = least like the designated
refluxed at 90°C on a waterbath. It was then cooled meat. An ANOVA-statistical technique was employed
and spray dried using an inlet temperature of 180°C for comparison of the sensory evaluations.
and an outlet temperature of 95°C, to obtain a flavor
powder. The reaction time for the refluxed beef RESULTS
hydrolysate (BH-R) and refluxed pork hydrolysate
(PH-R) was 2 h, while that for the refluxed chicken The meat flavors that obtained the highest
hydrolysate (CH-R) was 4 h.33-35 sensory evaluation scores were analyzed for protein,
carbohydrate, fat, ash and moisture contents (Table
Preparation of meat flavors (beef, pork, and chicken 2). These Maillard reaction flavors included BH10YE
flavor) through Maillard reaction containing yeast (beef hydrolysate, cysteine hydrochloride, yeast
extract extract and glucose), PH10YE (pork hydrolysate,
The mixture formulations and refluxing times yeast extract, methionine and glucose) and CH10YE
used for the Maillard reaction to prepare meat flavors (chicken hydrolysate, yeast extract, cysteine
(beef, pork or chicken) are shown in Table 1. hydrochloride and glucose).
Generally, the Maillard reaction mixtures contained The sensory evaluation on odor, flavor and
meat hydrolysate (beef, pork or chicken hydro- overall acceptability of commercial beef flavor (CB),
lysate), yeast extract, an amino acid and glucose. The refluxed beef hydrolysate (BH-R), and those products
reaction mixture was adjusted to pH 6.0 and refluxed prepared from Maillard reaction of beef hydrolysate,
at 90°C for the requisite period of time, followed by yeast extract, cysteine hydrochloride and glucose
spray drying to obtain a flavor powder. 33-35 (BH10YE and BH20YE) are presented in Table 3.
BH10YE obtained the highest mean evaluation score
Sensory evaluation tests for oder, flavor and overall acceptability, and this
The flavors were evaluated for sensory score was significantly different from that for the
acceptability by 40 untrained panelists who were commercial flavor CB (P≤0.05).

Table 1. Formulation and reaction time used for preparing meat flavors.

Items Beef flavor Pork flavor Chicken flavor

(g dry weight) BH10YE BH20YE PH10YE PH20YE CH10YE CH20YE

Beef hydrolysate 90 80 - - - -
Pork hydrolysate - - 90 80 - -
Chicken hydrolysate - - - - 90 80
Yeast extract 10 20 10 20 10 20
Cysteine hydrochloride 2 2 - - 4 4
Methionine - - 0.4 0.4 - -
Glucose 1 1 1 1 1 1
Reaction time (h) 2 2 2 2 4 4
222 ScienceAsia 26 (2000)

Table 2. Proximal analysis of meat flavors.

Samples % Protein* % Carbohydrate % Fat % Ash % Moisture

BH10YE 87.10 5.29 0.44 7.17 7.54

PH10YE 89.37 2.55 0.45 7.63 7.24
CH10YE 86.74 3.95 0.43 8.88 6.91
* Nx6.25

The sensory evaluation for odor, flavor and

Table 3. Acceptance scores1 of beef flavor samples. overall acceptability of pork flavors, including
commercial pork flavor (CP), refluxed pork
Score ± S.D. hydrolysate (PH-R) and the Maillard reaction of pork
Samples Odor Flavor Overall hydrolysate, yeast extract, methionine and glucose
1. CB 5.68±2.37a 6.00±2.13a 4.90±2.24a (PH10YE and PH20YE) are shown in Table 4. The
2. BH-R 5.65±1.82 a
6.68±1.57 a,b
5.48±1.65a,b mean sensory scores for odor, flavor and overall
3. BH10YE 7.18±0.94 b
7.59±0.78 b
6.53±1.46b acceptability for PH10YE was highest and this was
4. BH20YE 6.68±1.22 a,b
7.21±1.37 b
6.07±1.71a,b
not significantly different from PH20YE and PH-R.
a,b
All three were significantly different from the
Means with different superscripts in the same column are
significantly different at P≤0.05. commercial flavor CP. Indeed, the mean sensory
1
Highest score = 9 most similar to beef flavor, Lowest score = 1 evaluation scores for CP were very low.
= least similar to beef flavor. Table 5 shows the sensory evaluation scores for
odor, flavor and overall acceptability of commercial
Table 4. Acceptance scores1 of pork flavor samples. chicken flavor (CC), refluxed chicken hydrolysate
(CH-R) and the CH10YE and CH20YE Maillard
Score ± S.D. reaction products of chicken hydrolysate, yeast
Samples Odor Flavor Overall
extract, cysteine hydrochloride and glucose. No
1. CP 3.47±2.11 a
4.48±2.23 a
3.33±1.96a significant differences were found (P>0.05).
b b
2. PH-R 5.41±1.88 6.78±0.94 5.21±1.24b
3. PH10YE 6.38±0.94b 7.16±1.14b 5.72±1.39 b DISCUSSION
4. PE20YE 6.31±1.23b 6.34±1.43b 4.93±1.57b
a,b
Means with different superscripts in the same column are
The proximal analysis data in Table 2 showed
significantly different at P≤0.05. that the spray dried products BH10YE, PH10YE, and
1
Highest score = 9 most similar to pork odor or flavor, Lowest CH20YE had moisture contents in the range of 6-
score = 1 = least similar to pork odor or flavor. 7% (w/w) when they were in equilibrium with the
humidity in air. Their ash and fat contents were also
Table 5. Acceptance scores1 of chicken flavor samples. close. Since too high a fat content can cause rancidity
No significant differences were found (P≤0.05)
due to the degradation of unsaturated fatty acids by
oxidation reactions, some part of the fat had to be
Score ± S.D.
Samples Odor Flavor Overall removed during the preparation of meat hydro-
lysates. However, some of the flavor compounds in
a a
1. CC 6.50±1.78 7.17±1.16 5.57±1.74 a which characterized the meat flavors was derived
a a
2. CH-R 5.42±1.89 6.33±1.31 4.78±1.92 a from their fat content. The protein content in these
3. CH10YE 5.69±1.65 a 6.61±1.34 a 5.37±1.57 a flavor was high and at the same level. This protein
4. CH20YE 6.25±1.42 a 6.64±1.44 a 5.17±1.69 a can act as an encapsulating agent to trap volatile
a
Means with different superscripts in the same column are flavor components.36
significantly different at P≤0.05 Since the sensory evaluations scores for the beef
1
Highest score = 9 most similar to chicken odor or flavor, Lowest
score = 1 = least similar to chicken odor or flavor.
flavors that contained yeast extract, cysteine and
glucose (i.e., BH10YE and BH20YE) were higher than
those that did not (BH-R), the results suggested that
those compounds were important in helping to
enhance beef like flavor. However, the odor of yeast
extract is very strong, and if added in too high
quantity, it would dominate that of the beef flavor.
ScienceAsia 26 (2000) 223

Normally, beef hydrolysate possesses the flavor ACKNOWLEDGEMENTS

precursors characteristic of beef flavor. In the case
of the tested commercial flavor CB, it was not known The authors would like to thank to the National
whether it contained yeast extract in addition to beef Center for Genetic Engineering and Biotechnology
hydrolysate. (BIOTEC), National Science and Technology
For the pork flavors, PH10YE gave the best Development Agency (NSTDA), Ministry of Science,
sensory evaluation score, although this was not Technology and Environment, Bangkok, Thailand
significantly different from those of PH-R and for the financial support and Prof TW Flegel for
PH20YE. Thus, any of the three tested methods for reviewing the manuscript.
these would be suitable for preparing a good flavor.
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