Comparative Quality Evaluation of Physicochemical and Amylose Content Profiling in Rice Noodles from Diverse Rice Hybrids in China

Abstract

Rice noodles are one of southern people’s favorite foods in China, so it is important to find the suitable raw rice for rice noodle making. To study the effects of different rice varieties on the quality of fresh wet rice noodles and to explore the relationship between the quality of the rice and the quality of the fresh wet rice noodles, this study to compare the 12 hybrid rice varieties as raw materials analyzed the differences in the cooking quality, texture index, and sensory score of fresh wet rice noodles using the principal component analysis, membership function, and cluster analysis. The results showed that the quality of fresh wet rice noodles prepared from different hybrid rice materials differed significantly. The fresh wet rice noodles made from Liangyou 5836 are of good quality, and they are mainly characterized by a low rate of broken noodles and spit pulp value, high rice noodle hardness, good rice noodle elasticity, strong rice noodle chewiness, and low adhesiveness. Moreover, its sensory evaluation is also better than that of other varieties. The comprehensive evaluation of 12 hybrid rice varieties by subordinate function analysis also showed that Liangyou 5836 was the best. In addition, through principal component analysis and gray analysis, it was found that 14 related indicators of rice quality and fresh wet rice noodle quality were concentrated into four categories, among which gel consistency best reflects the quality of rice and fresh wet rice noodles. Through comprehensive analysis, it was found that an amylose content of about 22% and a gel consistency of less than 40 mm can be used as core indicators to screen varieties suitable for making rice noodles. This study is of great significance for the selection of hybrid rice for both rice quality and fresh wet rice noodle quality.

1. Introduction

With the improvement of living standards and the adjustment of diet structures, the direct consumption of rice per capita is gradually decreasing, especially in some developed areas. The comprehensive utilization of rice is the focus of the development of agricultural enterprise groups. They use food processing technology to make effective use of rice resources and greatly increase their value. In some developed countries, the consumption uses of rice are about 52% for direct consumption, 23% for food processing, and 25% for deep industrial processing. Such an industrial structure creates huge profits [1]. According to previous statistics, there were at least 15,000 kinds of convenience foods in the world, and there would be a trend towards convenience foods in mainstream food consumption [2].

As an important rice processing food, rice noodles have become an important part of the catering industry in southern China, and they have a large market in Southeast Asia due to their convenience, reasonable nutritional value, and rich taste. Rice noodles are a traditional product in southern China, mainly made of indica rice. For a long time, due to the limitations of rice quality and processing technology, the form and quality of rice noodle products were not able to keep up with the pace of modern life and the increasing demands of people’s living standards; as such, they were not widely promoted worldwide [3,4]. However, in recent years, rice has been developed into a variety of convenient rice noodles with novel tastes, and it has entered the food market due to its novel, delicious, convenient, and economically beneficial characteristics, creating an effective means of rice appreciation [5].

Rice noodles usually have rice as a raw material, and they are made through a series of processes such as cleaning, soaking, crushing or grinding, gelatinization, and extrusion or stripping [6]. Compared with dry rice noodles, fresh wet rice noodles are preferred by consumers because they are convenient, have a smooth taste, and are easy to process. They are also currently the most widely consumed breakfast rice noodle in China [7]. The variety of general and physicochemical characteristics of rice are the key factors that affect the processing quality of rice noodles. As the main raw material of rice noodle production, rice quality directly determines the taste and quality of rice noodles [8]. Previous research results show that the main rice quality indicators that affect rice noodle quality are amylose content, gel consistency, viscosity, and the gelatinization temperature [9]. Early indica rice with high amylose content (>20%) is commonly used to produce rice noodles. It is generally believed that the higher the amylose content, the greater the hardness of rice noodles, the lower the breakage rate and the cooking loss rate, and the better the sensory quality. The gelatinization temperature affects the structure of the starch gel network. If the gelatinization temperature is too high, the hardness of starch gel will be high, and if the gelatinization temperature is too low, the elasticity of the gel will be affected. The gelatinization grade is significantly and positively correlated with the broken rice noodle rate and the cooking loss rate [10,11]. The protein content is significantly and positively correlated with the taste, hardness, and chewiness of fresh wet rice noodles. The interaction of protein and starch makes the structure of the rice noodle gel more compact and stable. Therefore, the rice noodles produced with medium and high protein content (>7.1%) are of better quality [12]. Previous research results confirm that rice chalkiness, as an indicator of the quality of rice appearance, has a high correlation with amylose content, which can be used to predict rice noodle quality [13].

There are many varieties of rice in China that are vulnerable to regional and climatic factors. The quality of different indica rice varieties differs significantly, leading to the instability of the quality of fresh wet rice noodles, which hinders the further development of the fresh wet rice noodle industry [14]. Therefore, it is of fundamental significance to study the effects of different rice varieties on the quality of fresh wet rice noodles and to explore the relationship between the quality of the rice and the quality of the fresh wet rice noodles. The objectives of this work were: (1) the rice quality, cooking quality, texture index, and sensory scores of fresh wet rice noodles were determined and comprehensively evaluated using 12 hybrid rice varieties as raw materials to make fresh wet rice noodles; (2) the hybrid rice variety suitable for making fresh wet rice flour was screened; (3) it was to select the core indicators suitable for making rice noodles from the factors related to rice quality. This study screens out the hybrid rice varieties suitable for processing as fresh wet rice noodles, and it provides an important reference for the selection of rice noodle-specific rice.

2. Materials and Methods

2.1. Test Materials

The test materials were 12 hybrid rice varieties: Liangyou 347 (V1), Xiangliangyou 2 (V2), Chuanxiangyou 1101 (V3), Liangyou 121 (V4), Longliangyou 018 (V5), Liangyou 5836 (V6), C–Liangyou 343 (V7), Huailiangyou 608 (V8), Longliangyou 750 (V9), Shenliangyou 5183 (V10), T–you 817 (V11), and Liangyou 336 (V12). All seeds were provided by the Rice Research Institute of Hunan Agricultural University.

2.2. Experimental Design and Methods

This study was conducted in Yanxi Town, Liuyang City, Hunan Province, China in 2018. The plot area of each variety was 40 m², and each experiment was repeated three times. Randomized complete block design was applied in this study. In the experiment, 150 kg/hm² of pure nitrogen, 75 kg/hm² of P₂O₅, and 75 kg/hm² of K₂O were applied. Nitrogen fertilizer was applied at the proportion of 40% base fertilizer, 30% tillering fertilizer, and 30% panicle fertilizer. Phosphate fertilizer was used as the base fertilizer. Potassium fertilizer was applied at the ratio of 50% base fertilizer and 50% panicle fertilizer. Field management parameters, such as water management and pest control, refer to local cultivation methods.

Neat and consistent rice grains were selected for the production of fresh wet rice noodles. The hulled rice was soaked for 3 h at 30 °C, and the water volume was adjusted to meter: water = 1:1.8. The soaked hulled rice was ground and passed through the 60 mesh sieve. After fully mixing, the milled slurry was put it into the steamer. Each plate in the steamer was distributed with 60 g, the temperature was set to 100 °C, and the time was set to 90 s. After cooling, these fresh wet rice noodles should be cut into strips with lengths of 20 cm and widths of 8 mm.

2.3. Measurement Items and Methods

2.3.1. Rice Quality

The harvested rice was threshed and dried, and it was stored at a constant temperature and humidity for 90 days to determine its quality. Then, 100 g of rice was weighed and poured into the grain sheller. After shelling, the residual grains in the sample were detected, and the brown rice and grains are weighed. Then, 100 g of brown rice was weighed and poured into a precision machine for grinding. After the rice sample cooled to room temperature, the milled rice was weighed.

Brown rice rate (%) = brown rice weight/(sample grain weight − non shelled grain weight) × 100.

(1)

Milled rice rate (%) = milled rice weight/brown rice weight × brown rice rate.

(2)

Amylose content was determined by iodine blue colorimetry [15]. The details are as follows: 20 mg of rice noodles were accurately weighed, 0.1 mL of absolute ethanol was added, and then, 1.8 mL of 1 mol/L NaOH solution was added. The mixture was evenly mixed and placed in an oven at 65 °C for 1 h. The sample was taken out of the oven and cooled to room temperature. Then, 50 μL of the dispersible solution was absorbed and added to the prepared centrifuge tube. Another 100 μL 1 mol/L sodium acetate solution was added, which acidified the sample. Then, 100 μL 0.04% iodine solution was added; the mixture was shaken, and the absorbance value was measured at 620 nm.

The gel consistency of rice was determined according to the method described by Cagampang et al. [16]. The details are as follows: 100 mg of rice noodles with water content of about 12%, of each rice variety, was weighed and poured into two test tubes. Then, 0.2 mL 95% ethanol thymol blue solution was added into each tube. The test tubes were shaken gently to make the rice noodles fully disperse without agglomeration. Then, 2.0 mL of 0.2 mol/L KOH solution was added. The test tubes were placed in a boiling water bath for 8 min. After heating, the test tubes were removed and cooled for 5–10 min at room temperature. Then, the test tubes were placed into the ice water bath and frozen for 20 min. Then, they were placed horizontally for 1h and observed, and the length of the rice glue was recorded.

2.3.2. Cooking Quality of Fresh Wet Rice Noodles

The broken noodle rate of the fresh wet rice noodles was determined with reference to the method of Luo et al. [17]. First, 20 pieces of fresh wet rice noodles of 20 cm in length were randomly selected. After cooking in 500 mL boiling water for 1 min, the rice noodle samples were picked up and filtered with supercooled water. The number of rice noodles above 10 cm (x1) was recorded, and the broken rate was calculated according to the following formula:

Broken noodle rate (%) = (20 − x1)/20 × 100.

(3)

The spit pulp value of the fresh wet rice noodles was determined with reference to the method of Lei et al. [18]. First, a 20 g rice noodle sample (m0/g) was weighed, and the moisture content of the rice noodles (ω) was weighed. It was then boiled in 500 mL boiling water for 2 min, and the volume of the soup was fixed to 500 mL. Then, 50 mL was sucked into a vessel (m1/g) with a constant weight and placed at (105 ± 2) °C to dry to a constant weight (m2/g). The pulp spitting value was calculated according to the following formula:

Spit pulp value (%) = (10 × (m2 − m1))/(m0 × (1 − ω))×100.

(4)

2.3.3. Texture Determination of Fresh Wet Rice Noodles

The texture characteristics were analyzed using a TA–XT2i texture analyzer (Stable Micro System, London, UK). The prepared rice noodles were cut into 5 cm long pieces. Then, two layers were measured each time and were placed in the center of the stage of the texture analyzer. The velocity before measurement, velocity during measurement, velocity after measurement, compression ratio, time interval between two compressions, and trigger force of the texture analyzer were, respectively, set to 2 mm/s, 1 mm/s, 1 mm/s, 50%, 3.0 s, and 5 g [19]. The texture measurement indices include rice noodle hardness, adhesiveness, rice noodle elasticity, and rice noodle chewiness, and each sample was repeated six times.

2.3.4. Sensory Evaluation of Fresh Wet Rice Noodles

Sensory evaluation is a science that measures, analyzes, and explains the interaction between food and other substances, and it can be evaluated through human taste, touch, vision, smell, and hearing. Sensory evaluation involves five human sensory organs, including taste evaluation, touch evaluation, visual evaluation, olfactory evaluation, and auditory evaluation. It is used because the quantitative indicators usually measured by chemical methods cannot accurately explain the overall situation of a sensory evaluation and because chemical detection cannot fully explain the interaction of various sensory elements. Therefore, sensory evaluation plays an indispensable role in the food industry [20]. The effectiveness of fuzzy logic in the sensory evaluation of food products is mainly admissible in cases wherein quality aspects perceived by consumers are difficult to relate with the responsible chemical or physical component attributes [21]. In the process of fuzzy approach, sensory panels have been requested to give a note on the range of intensity in scale, which could be later converted into a score ranging between 0 and 100 [22]. In this study, the sensory evaluation refers to Lei’s method [18]. A sensory evaluation team consisting of seven people conducted sensory evaluation of rice noodles, as detailed in

Table 1. Criteria for sensory evaluation of wet rice noodles.

Level 1 Indicators/Scores	Secondary Indicators/Scores	Specific Characteristic Description: Score
Smell/25 points	Rice aroma/5 points	With the rice aroma, there is a rich aroma: 22–25 points
		With rice aroma, the aroma is not obvious: 18–21 points
		No rice aroma, but no peculiar smell: 15–17 points
		No rice aroma, and peculiar smell: 0–14 points
Appearance/35 points	Color/10 points	Color is white: 8–10 points
		Color is normal: 5–7 min
		Color is yellow or gray: 0–4 points
	Gloss/10 points	Obvious gloss: 8–10 points
		Slightly shiny: 5–7 min
		Matte: 0–4 points
	Structure/15 points	The structure is tight, the chopsticks do not easily break the strip, there is no merging of strips, crushing, or cracking: 10–15 points
		No broken noodles, parallel strips, crushed powder, a small amount of cracking: 5–9 min
		There is crushed powder, it is easy to break the noodles or have a parallel strip, cracking: 0–4 points
Texture characteristics/40 points	Adhesiveness/10 points	Smooth and non–sticky: 8–10 points
		Basic non-sticky teeth: 5–7 points
		Sticky teeth: 0–4 points
	Rice noodle hardness/10 points	Moderate hardness: 8–10 points
		Slightly hard or soft: 5–7 points
		Very soft or very hard: 0–4 points
	Sense of strength/10 points	Chewy: 8–10 points
		Slightly chewy: 5–7 points
		Non-chewy: 0–4 points
	Rice noodle elasticity/10 points	Elasticity: 8–10 points
		Elasticity is average: 5–7 points
		Insufficient elasticity: 0–4 points

. The highest score and the lowest score were removed, and the average value was taken.

2.4. Data Processing and Analysis

Microsoft Excel 2013 was used for data entry and organization, and SPSS 25.0 software was used for single-factor (ANOVA) analysis. The mean variance was separated using the Duncan multiple comparison test, expressing the level of significant difference as p < 0.05. The K-means algorithm and Euclidean distance of OriginPro 2023 (64 bit) Beta3 was used to cluster the samples. The gray relational grade analysis referred to the method of Su et al. [23]. The membership function method was used to comprehensively evaluate the different hybrid rice varieties [24]. The specific subordinate function value calculation formula of each index of each sample was as follows:

Xu = (X − Xmin)/(Xmax − Xmin)

(5)

Xu=1 − (X − Xmin)/(Xmax − Xmin)

(6)

In the formula, X is the measured value of an index of the test sample, and Xmax and Xmin are the maximum and minimum values of the index in all samples, respectively. If the measured indices were positive correlation, Equation (2) was used to calculate the membership value, and Equation (3) was used for negative correlation. Finally, the membership function values of each index for each sample were accumulated, and the average value was taken.

3. Results

3.1. Rice Processing Quality of Different Hybrid Rice Varieties

The processing quality is used to evaluate the processing quality of rice. It mainly comprises the brown rice rate and the milled rice rate. These are important grading indices of high-quality rice. The brown rice rate and the milled rice rate differ between the different varieties (Figure 1A,B). The brown rice rate of different varieties is 74.03%–82.07%. The difference between C–Liangyou 343 (V7) and Liangyou 347 (V1) is the most significant. The former is 10.86% higher than the latter. The milled rice rate of different varieties is 61.59%–71.77%. The difference between Liangyou 121 (V4) and Liangyou 347 (V1) is the most significant. The former is 16.53% higher than the latter. In addition, there was no significant difference in the brown rice rate and milled rice rate between Liangyou 121 (V4), C–Liangyou 343 (V7), Huailiangyou 608 (V8), Longliangyou 750 (V9), Shenliangyou 5183 (V10), and Liangyou 336 (V12).

3.2. Rice Cooking Quality of Different Hybrid Rice Varieties

Rice cooking quality refers to the physical and chemical characteristics of rice during cooking. It mainly comprises amylose content, gel consistency, etc. There are differences in amylose content and gel consistency among the different varieties (Figure 2A,B). The amylose content of different varieties ranges from 13.32–35.00%. The difference between Liangyou 336 (V12) and Shenliangyou 5183 (V10) is the most significant. The former is 162.76% higher than the latter. The gel consistency of the different varieties ranges from 29.67–68.33%. The difference between Liangyou 336 (V12) and Liangyou 5836 (V6) is the most significant. The former is 130.30% higher than the latter.

3.3. Cooking Quality of Fresh Rice Noodles from Different Hybrid Rice Varieties

The cooking quality of fresh rice noodles processed with different varieties of rice differs among these varieties (Figure 3A,B). The broken noodle rate of Liangyou 336 (V12) was the highest in the cooking quality of fresh rice noodles, reaching 43.33%. There was no significant difference between Longliangyou 750 (V9) and Liangyou 336 (V12). The second is Longliangyou 018 (V5). However, the broken noodle rate of Liangyou 5836 (V6) was the lowest at 6.67%. There was no significant difference between Chuanliangyou 1101 (V3) and Liangyou 5836 (V6). The spit pulp value of Longliangyou 018 (V5) was the highest in the cooking quality of fresh rice noodles, reaching 20.04%. The second was Liangyou 336 (V12). However, the spit pulp value of Chuanliangyou 1101 (V3) was the lowest, at 6.12%.

3.4. Texture Indices of Fresh Rice Noodles from Different Hybrid Rice Varieties

For fresh rice noodles, the masticatory taste and its tissue structure are important texture indices. Therefore, the rice noodle hardness, adhesiveness, elasticity, and chewiness texture indices represent the quality of fresh rice noodles to some extent. According to the texture index of fresh rice noodles, the hardness, elasticity, and chewiness of Chuanxiangyou 1101 (V3) were significantly different from those of the other varieties (Figure 4A,C,D). Among them, the hardness and elasticity of Chuanxiangyou 1101 (V3) are not significantly different from Liangyou 5836 (V6), but they are the most different from Longliangyou 018 (V5). The chewiness of Chuanxiangyou 1101 (V3) and Longliangyou 750 (V9) are the most different. The former is 307.41% higher than the latter. Among the texture indices of fresh rice noodles, Longliangyou 750 (V9) has the highest adhesiveness, reaching 686.68 (Figure 4B). The second is Liangyou 336 (V12). However, the adhesiveness of Liangyou 347 (V1) was the lowest at 126.43. It was significantly different from Chuanliangyou 1101 (V3) and Liangyou 5836 (V6).

3.5. Sensory Evaluation of Fresh Rice Noodles from Different Hybrid Rice Varieties

There are differences in the sensory evaluation indices of fresh rice noodles produced with different varieties of rice (Figure 5A–C). Xiangliangyou 2 (V2) had the highest smell score, reaching 17.8. It is significantly different from Liangyou 5836 (V6) and Chuanxiangyou 1101 (V3). The appearance score of Liangyou 5836 (V6) was the highest, reaching 29. The texture characteristics score of Liangyou 347 (V1) was the highest, reaching 30. There are significant differences between Chuanxiangyou 1101 (V3) and the other varieties. However, Longliangyou 750 (V9) had the lowest scores in terms of smell, appearance, and texture characteristics. According to the three indicators, Chuanxiangyou 1101 (V3) had the highest total score in terms of sensory evaluation (Figure 5D). The fresh rice noodles produced by it have a good rice flavor, no parallel strips, a smooth taste, and an elastic texture. Liangyou 5836 (V6) does not differ from it. However, Longliangyou 750 (V9) has the lowest total score in terms of sensory evaluation. Its fresh rice noodles have no rice flavor, high adhesiveness, and poor chewiness.

3.6. Principal Component Analysis of Different Hybrid Rice Varieties

Principal component analysis (PCA) was used to evaluate the rice quality traits and fresh rice noodle quality traits of the different varieties. PC1 and PC2 accounted for 65.42% and 13.58% of the contribution rates, respectively. Different varieties have different correlations with different characteristics (Figure 6). The cumulative contribution rate of the two principal components was up to 70%. This shows that the two main components extracted represent most of the information related to the rice quality and fresh wet rice noodles of 12 hybrid rice varieties. The eigenvalue of PCA1 was 9.16. The indicators of positive eigenvalues include hardness, elasticity, chewiness, smell, appearance, texture characteristics, and the total score of sensory evaluation; other indicators pointed to negative eigenvalues. The eigenvalue of PCA2 was 1.9. The indices with increased positive eigenvalues include the amylose content, gel consistency, broken noodle rate, spit pulp value, adhesiveness, smell, elasticity, and the total score of sensory evaluation. Other indicators pointed to negative eigenvalues.

Through the principal component analysis of the 12 hybrid rice varieties, it was found that the scores of Chuanxiangyou 1101 (V3) and Liangyou 5836 (V6) for PC1 were higher than those of the other varieties; this was mainly reflected in terms of hardness, elasticity, and chewiness, as well as sensory characteristics, indicating that the fresh wet rice noodles of these two varieties had the best quality. The scores of Liangyou 347 (V1) and Liangyou 336 (V12) on PC2 were higher than those of the other varieties, which is mainly reflected in amylose content and gel consistency.

3.7. Evaluation of the Membership Function of Different Hybrid Rice Varieties

The membership function analysis method was used to comprehensively evaluate the rice quality and fresh rice noodle quality (Figure 7A,B). The results showed that Liangyou 5836 (V6), Chuanxiangyou 1101 (V3), Xiangliangyou 2 (V2), and Liangyou 347 (V1) were the top four varieties in the mean value of the membership function. Longliangyou 750 (V9) had the lowest mean membership function. Moreover, Liangyou 5836 (V6), Chuanxiangyou 1101 (V3), Xiangliangyou 2 (V2), and Liangyou 347 (V1) showed good rice quality and fresh rice noodle quality. Longliangyou 750 (V9) performed the worst.

3.8. Cluster Analysis of Different Hybrid Rice Varieties

Cluster analysis was conducted on 14 indices of rice quality and fresh wet rice noodle quality of 12 hybrid rice varieties, and a cluster tree diagram was produced. It can be seen from Figure 8 that the 12 varieties are obviously divided into three categories. The first category includes Liangyou 5836 (V6), Chuanxiangyou 1101 (V3), Xiangliangyou 2 (V2), and Liangyou 347 (V1). The rice quality and fresh rice noodle quality of these varieties are the highest. The second category includes T–you 817 (V11), Huailiangyou 608 (V8), Shenliangyou 5183 (V10), and C–liangyou 343 (V7). The rice qualities and fresh rice noodle qualities of these varieties are average. The third category includes Liangyou 336 (V12), Longliangyou 750 (V9), Longliangyou 018 (V5), and Liangyou 121 (V4). These varieties have poor rice and fresh rice noodle qualities.

3.9. Grey Analysis of Amylose Content and Quality Indices of Rice and Fresh Rice Noodles

The main components of rice starch are amylose and amylopectin. Amylose content is closely related to rice texture. It is considered an important influencing factor for rice texture. High or low amylose content leads to poor cooking quality. Figure 9 shows the Grey analysis of amylose content and other quality indices. The Grey correlation between gel consistency and amylose content was the largest at 0.40. This also confirms the result that the distance between amylose content and gel consistency in the principal component analysis is close, and the index similarity is high.

4. Discussion

Rice quality is a quantitative genetic trait that is controlled by multiple micro genes and is easily affected by environmental factors. There are some limitations in evaluating rice quality by a single indicator, so multiple indicators are needed for a comprehensive evaluation. Whether the rice is suitable for the processing of fresh rice noodles is determined by two major indices of rice quality and fresh rice noodle quality. However, these different factor components are independent and closely related to each other. In this study, 14 quality indices were measured for 12 hybrid rice varieties. In terms of rice quality, Liangyou 121 (V4), C–Liangyou 343 (V7), Huailiangyou 608 (V8), Long Liangyou 750 (V9), Shenliangyou 5183 (V10), and Liangyou 336 (V12) all showed a good brown rice rate and milled rice rate. The amylose content and gel consistency of Liangyou 336 (V12) were the highest. The amylose content of high-quality rice is 13.0%–22.0%, and the gel consistency is ≥50 mm [25]. Combined with the above two indices, of the 12 hybrid rice varieties in this study, only C–Liangyou 343 (V7) meets the requirements of high-quality rice in terms of amylose content and gel consistency. As far as the quality of fresh rice noodles is concerned, the broken noodle rate and spit pulp value of Longliangyou 018 (V5), Longliangyou 750 (V9), and Liangyou 336 (V12) are in the top three of the 12 hybrid rice varieties. This shows that the fresh rice noodles processed with these three varieties break easily, and the soup easily becomes turbid during cooking. After analyzing the texture index of the fresh rice noodles, it was found that the hardness and chewiness of fresh rice noodles processed by Longliangyou 018 (V5), Longliangyou 750 (V9), and Liangyou 336 (V12) were also poor. On the other hand, Liangyou 347 (V1), Xiangliangyou 2 (V2), Chuanxiangyou 1101 (V3), and Liangyou 5836 (V6) all had relatively low broken noodle rates, spit pulp values, and adhesiveness, as well as relatively high hardness, elasticity, and chewiness. In addition, the sensory evaluation of fresh rice noodles is the most direct way to address consumers’ feelings and preferences, although the quality of rice can be indirectly evaluated by rice’s physical and chemical indicators and instruments. However, until now, sensory evaluation methods have been used internationally to evaluate the taste quality of rice [26]. The same is true for the sensory evaluation of fresh rice noodles. In this study, Xiangliangyou 2 (V2), Chuanxiangyou 1101 (V3), and Liangyou 5836 (V6) exhibited a good smell. At the same time, Liangyou 5836 (V6) also has a good appearance. Liangyou 347 (V1) and Chuanxiangyou 1101 (V3) showed good texture characteristics. According to the sensory scores of the fresh rice noodles, the comprehensive scores of Chuanxiangyou 1101 (V3), Liangyou 5836 (V6), and Liangyou 347 (V1) are more than 70, indicating that consumers like them very much. However, the comprehensive scores of Shenliangyou 5183 (V10), C–Liangyou 343 (V7), Longliangyou 018 (V5), Liangyou 336 (V12), and Longliangyou 750 (V9) were below 60 points.

Principal component analysis can simplify complex variables into a few comprehensive variables, which can effectively prevent multiple data problems in the process of identifying rice quality and fresh wet rice noodle quality. At the same time, complete information for each indicator can be obtained to a great extent. Through principal component analysis, many independent and closely related indices can be classified by dimension reduction statistics [27]. Through principal component analysis, 14 related indices of rice quality and fresh rice noodle quality were grouped into four categories. Among them, the brown rice rate and the milled rice rate belong to the same category. The broken noodle rate, the spit pulp value, and the adhesiveness belong to the same category. Amylose content and gel consistency belong to the same category. The remaining indices belong to one category. Therefore, in the subsequent related studies, representative indices can be selected from the four categories to preliminarily evaluate the quality of fresh rice noodles.

Amylose content was one of the important factors affecting the texture of fresh rice noodles [28,29,30]. Early indica rice with high amylose content (>20%) is commonly used to produce rice noodles. The higher the amylose content, the greater the hardness of the rice noodles, the lower the broken noodle rate and cooking loss rate, and the better the sensory quality [31]. Therefore, this study analyzed the correlation between the other 13 indices and amylose content through Grey analysis. It is concluded that gel consistency is the index most relevant to amylose content. This also reflects the result that amylose content and gel consistency are the closest and have the highest similarity in the principal component analysis. Therefore, in the determination of amylose content, the determination of gel consistency can be increased. The accuracy of the results produced by the evaluation of the fresh rice noodles’ quality was increased by combining the two indices. When the conditions for amylose content determination are limited, the determination of gel consistency can replace the determination of amylose content to reflect the evaluation results of fresh rice noodle quality. The same study also confirmed that the quality of rice noodles was mainly related to amylose content and gel consistency, and proteins and lipids had little influence on it. Rice noodles with amylose content of 23–28% and gel consistency of 30–45 mm could produce better quality rice noodles [32,33].

However, a single index cannot adequately reflect the quality of rice and fresh rice noodles. The membership function method is a unified quantitative calculation of various values, which is then used to make a comprehensive comparison. It can comprehensively reflect the overall performance of a variety. In this study, 12 hybrid rice varieties were obtained using the membership function method. The variety with the best comprehensive performance was Liangyou 5836 (V6). In addition, cluster analysis is a statistical method that classifies the relatively independent and related individuals according to their closeness and similarity in nature. It can classify and comprehensively investigate a large number of individuals. In this study, 14 indices related to rice quality and fresh rice noodle quality were used to cluster 12 hybrid rice varieties. There are three obvious categories, among which Liangyou 5836 (V6) and Chuanxiangyou 1101 (V3) are grouped together. Through this study, we found that the amylose content of hybrid rice is about 22%, and the gel consistency is less than 40 mm, which can produce high-quality rice noodles. Therefore, in future rice breeding processes, the amylose content and gel consistency should be balanced in the selection of hybrid rice noodles.

5. Conclusions

The complex characteristics related to rice quality make it difficult to evaluate the characteristics of fresh wet rice noodles. Therefore, in addition to measuring many indicators, it is also necessary to comprehensively use different evaluation methods to evaluate quality. Principal component analysis, the membership function method, cluster analysis, and Grey correlation analysis can be used to evaluate the relationship between rice quality and the quality of fresh wet rice noodles. The quality evaluation of rice noodles mainly involves sensory evaluation and objective evaluation. In the sensory evaluation, taste had the most significant effect on the total score. In the total texture analysis, hardness and elasticity can be used as key indicators to evaluate the quality of rice noodles. Rice noodle quality is largely determined by rice quality. Among the factors associated with rice quality, amylose content of about 22% and gel consistency of less than 40 mm can be used as core indicators to screen varieties suitable for making rice noodles. In this study, it was found that Liangyou 5836 (V6) was a suitable hybrid rice variety for making fresh wet rice noodles. These results can provide a reference for the evaluation of rice quality and the quality of fresh wet rice noodles, and they also provide new ideas for food processing enterprises to produce new functional rice products.