Journal of Chemistry

Journal of Chemistry / 2016 / Article

Research Article | Open Access

Volume 2016 |Article ID 3626581 | 7 pages | https://doi.org/10.1155/2016/3626581

Instrumental and Sensory Analysis of the Properties of Traditional Chinese Fried Fritters

Academic Editor: Yiannis Kourkoutas
Received17 Jul 2016
Revised24 Sep 2016
Accepted28 Sep 2016
Published19 Oct 2016

Abstract

The quality of traditional Chinese fried fritters is typically measured using human sensory evaluation techniques and physicochemical indices, the process of which is laborious and time-consuming. This study aimed to investigate the relationship between instrumental parameters, sensory criteria, and physicochemical indices. Significant correlations were found using principle component analysis. Volume, fat, texture, palatability, and instrumental parameters (hardness, fracturability, springiness, and gumminess) were found to be the main factors influencing the quality of Chinese fried fritters by principal component analysis (PCA) and instrumental methods, which were satisfactory replacement for human evaluation in correlation testing.

1. Introduction

Fried fritters are a type of traditional Chinese breakfast food and a popular snack, due to a low price and a distinctive flavor [1]. The unique taste comes from the crisp surface, loose texture, and fried flavor. China produces approximately 120 thousand tons of fritters per year, worth 2.4 billion yuan. The income of the “Yong he King” chain from the sale of fried fritters in 2003 was reported to be 300 million yuan. Classified as a traditional Chinese food, fritters are not only eaten by the Chinese but also widely consumed abroad in countries including Japan, Korea, Singapore, and Russia. However, concerns over food quality standards have become a matter of debate all over the world and have gained significant attention in China.

Since 1990, many scientific studies have focused on fried fritters. Most have centered on the development of a new formula to enhance the quality and safety [24]. Others have investigated the correlation between wheat flour and the quality of the final product [5, 6]. However, the evaluation criteria have been based only on human sensory evaluation and physicochemical indices. Sensory evaluation is commonly considered to be the best qualitative method of assessment and no instrumental techniques are thought to exist to adequately replace human evaluation of food quality. However, a range of shortcomings of the human evaluation method hamper its usage, such as inconsistent evaluation standards and the relatively laborious and time-consuming process involved [7].

A significant correlation between instrument-based and subjective sensory methods has been difficult to establish and a reliable relationship is not always feasible, according to the research of Harker et al. [8]. Empirical and imitative instrumental tests have correlated with sensory texture descriptors with varying degrees of success, for fruits [7, 911], fried food [12, 13], bread [14], and meat products [15]. Texture profile analysis (TPA) has been used for many years as a substitute for human teeth to detect properties including hardness, fracturability, adhesiveness, springiness, cohesiveness, gumminess, chewiness, and resilience [16].

In the present study, 25 fried fritters made using different formulas were measured using both texture analysis and sensory evaluation. In order to determine the most effective instrumental parameter for the prediction of fried fritter texture, correlations between sensory perception and physicochemical and texture properties of fried fritters were investigated.

2. Materials and Methods

2.1. Ingredients

Fried fritters were produced using 25 different formulas. The ingredients added for each formula were identical, and the differences between formulas were due to the amounts of the ingredients added. Flour was obtained from Tianjin (China). The leavening agent used included sodium bicarbonate (SB), gluconic acid-δ-lactone (GdL), calcium biphosphate (CB), glycerol monolaurate (GML), yeast, and amylomaize starch (AMS).

2.2. Physicochemical Properties

The moisture content of the fried fritters was determined by vacuum drying. Samples were cut into pieces (approximately 100 g) and dried in a vacuum oven at 90°C until the weight reached a constant value (modified method 44-40 [AACC, 2000]). Lipid content was measured gravimetrically following extraction using an extraction unit (SOXTEC System HT2, 1045) with petroleum ether (boiling range 30–60°C) [13]. The volumes of the samples were determined using the rapeseed displacement method [17] and five samples of each formula were selected for volume testing. Specific volume was calculated from the ratio of volume to weight. All physicochemical measurements were carried out in triplicate.

2.3. Sensory Evaluation

Nine individuals participated in the sensory evaluation test, following completion of a series of training sessions over a one-month period. Training consisted of identifying and rating the color, odor, palatability, and texture of the fried fritter samples. The criteria for each index in the sensory evaluation are listed in Table 1.


Attribute Criteria

ColorColor and brightness10
Gold8~10
Light yellow or brown4~8
Gray or dark brown1~4
OdorAroma and taste10
Strong aroma of deep fried and no smell8~10
Strong aroma of deep fried and slightly alkaline or sour taste4~8
Heavier slightly alkaline or sour taste1~4
PalatabilityThe extent of tenacity and crisp and chewiness10
Crisp and refreshing, moderately tenacious, and easy to chew8~10
Too soft, too hard, or difficult to chew1~4
Middle4~8
TexturePore size and uniformity10
Large and uniform pore8~10
Large pore but general uniformity4~8
Small pore and poor uniformity1~4

2.4. Instrumental Measurements

TPA instrumental measurements were made using AXT-2i Texture Analyzer (Stable Micro System Ltd., Surrey, UK). Seven samples were selected from each formula for TPA testing. During the testing process, samples were kept separate from any factors that could potentially influence the results, such as samples temperature and air flow. Results were averaged following removal of values outside of two standard deviations. Specific TPA parameters were as follows: probe DPH-3PB, sensitivity 10 g, test speed 5.0 mm per min, speed before test 5.0 mm per min, speed after test 5.0 mm per min, test distance 70% (sample thickness), automatic trigger, and access rate 200 PPS. In instrumental measurement, many indices were obtained including hardness, fracturability, adhesiveness, springiness, cohesiveness, gumminess, chewiness, and resilience.

2.5. Statistical Analysis

Principal component analysis and correlation testing were carried out using the SPSS 17.0 software package (SPSS, Chicago, IL, USA). All instrumental and sensory data were subject to Duncan’s Multiple Range Test, with the level for statistical significance set at . Correlation coefficients were obtained using Pearson’s Bivariate Correlation. Principle component analysis (PCA) was conducted to summarize the relationships between physicochemical properties and the sensory parameters.

3. Results and Discussion

All results pertaining to the quality of the fried fritters are listed in Tables 2, 3, and 4. In Table 2, moisture content of all samples ranged from 27.27% to 39.67%, fat content from 5.58% to 14.87%, and volume from 2.22 to 3.24. In Table 3, sample 8 had the best odor, sample 24 had the best color and texture, and sample 25 had the best palatability. In Table 4, sample 6 was best at hardness, gumminess, and chewiness and sample 3 had the best fracturability.


SampleMoisture content (%)Fat content (%)Volume (%)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

Results as mean ± SD. Different superscripts in the same row denote significant differences ().

SampleOdorColorTexturePalatability

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

Results as mean ± SD. Different superscripts in the same row denote significant differences ().

Sample Hardness (g)FracturabilityAdhesivenessSpringinessCohesivenessGumminessChewinessResilience

1
2
3
4
5