Fermented Rice Flour Research Articles

Study on physicochemical characteristics of local colored rice varieties (black, red, brown, and white) fermented with lactic acid bacteria (SBM.4A).

In this study, the physicochemical properties of local colored rice flour were studied after modification through fermentation with lactic acid bacteria (LAB) SBM.4A. SBM.4A was LAB isolated from the rice washing water and was in the cladogram of the Pediococcus pentosaceus strain SRCM102739 CP028266.1 and Pediococcus pentosaceus strain SRCM102738 CP028264.1. The studied rice varieties were wakacinda (white rice), wakawondu (red rice), warumbia (brown rice), and wakaombe (black rice). Characterizations of both fermented and native rice flour included chemical composition, FTIR profile, crystallinity, morphology, and pasting properties. Fermentation did not introduce new chemical functional groups to the flour and only slightly increased crystallinity from approximately 22.5% to 25.05%. In contrast, fermentation greatly affected the chemical composition and pasting properties of rice flour. Protein content of the fermented flour increased up to 214% relative to the native rice flour. Effect of fermentation on pasting properties varied between rice varieties. Increase in peak and final viscosities was observed in red, brown, and black rice. The opposite effect was found in white rice. However, fermentation improved the stability of flour to retrogradation for all rice varieties. These showed that the fermentation improved the properties of the local-colored rice flour and may widen their application as food ingredients.

Effect of Lactobacillus acidophilus Fermentation on the Quality of Glutinous Rice Products

AbstractThe effect of Lactobacillus acidophilus and spontaneous fermentation on the quality characteristics of glutinous rice products are investigated in this study. Optimization of the product quality based on orthogonal experiments on the four fermentation conditions ensure that the product still has good sensory properties when stored during its shelf life at room temperature. The optimal fermentation conditions based on the range analysis are the mass ratio of glutinous rice, corn and rice 8:1:1, L. acidophilus inoculum of 8%, fermentation temperature of 37 °C, and fermentation time of 28 h. Under this condition, rice products’ hardness, viscosity, elasticity, cohesiveness, and taste significantly increase compared to the spontaneously fermented products. The pasting characteristics, water absorption index, thermodynamic properties, short‐range ordered structure, and microstructure of two kinds of fermented rice flours are analyzed. L. acidophilus fermented rice flour is more prone to pasting and ageing, with a higher proportion of short‐chain amylopectin in starch and lower final viscosity and water absorption, with a denser and smoother internal structure. In conclusion, fermentation improves the properties of glutinous rice flour and its products, and L. acidophilus fermentation is more effective than spontaneous fermentation.

Effect of sodium bicarbonate on the physicochemical properties of fermented rice flour and quality characteristics of fermented semi-dried rice noodles.

Considering the effect that fermentation can improve the quality of rice noodles, and given that fermented rice noodles usually have a significantly acidic taste that is not generally acceptable to consumers, this study aimed to neutralize or eliminate the acidic taste of fermented rice noodles by adding sodium bicarbonate, and improve the quality of fermented rice noodles. The physicochemical properties of fermented rice flour and quality characteristics of fermented semi-dried rice noodles were investigated in this study in relation to the addition of sodium bicarbonate (0∼0.5%, w/w). With the increase of sodium bicarbonate addition, the pH value was increased, and lipid and protein content were decreased in rice flour. Meanwhile, thermal properties and farinograph properties showed that the pasting temperature, dough water absorption, dough development time and dough stability time of rice flour increased with the addition of sodium bicarbonate. Pasting properties and rheological properties results showed that a small amount of sodium bicarbonate (0∼0.1%) could increase the pasting viscosity, storage modulus (G'), and loss modulus (G″) of rice flour. Additionally, the hardness and chewiness of semi-dried rice noodles increased with the addition of sodium bicarbonate from 0 to 0.1%. With the addition of a small amount of sodium bicarbonate (0∼0.1%), x-ray diffraction showed that it could increase the crystallinity of semi-dried rice noodles. Low-field nuclear magnetic resonance showed that A21 increased, and A22 and A23 decreased in semi-dried rice noodles. Scanning electron microscope showed that it could enhance the starch-protein interaction and starch-protein formed an ordered and stable network structure. Finally, the principal component analysis showed that the chewiness, texture and eating quality of semi-dried rice noodles were the best with the addition of sodium bicarbonate at 0.1%. This study provides practical value for the application of alkali treatment in rice products and provides a reference for the improvement of related rice noodles products.

Effects of water, guar gum, potassium chloride, and drying methods on quality and rehydration time of instant fermented rice noodles

SummaryQuick rehydration is the most important characteristic of instant noodles. This study investigated the effects of ingredients on the production and drying methods, the quality, and the rehydration time of instant fermented rice noodles. The dried fermented rice flour was mixed with different amounts of water (80%, 85%, and 90%), guar gum (0.5%, 1.0%, and 1.5%), and potassium chloride (1%, 2%, and 3%). The noodles were dried in a microwave vacuum oven and compared with drying in a hot air oven and a microwave continuous oven. The optimum contents of water, guar gum, and potassium chloride were 80%, 1.5%, and 2%, respectively, because water at 80% resulted in the shortest rehydration time and the highest firmness, guar gum at 1.5% could increase firmness and the water absorption ability to produce the highest cooking yield and firmness with the lowest cooking loss, and potassium chloride at 2% resulted in the shortest rehydration time. Microwave vacuum drying produced the fastest rehydration in hot water for 2 min and the quality of these rehydrated noodles was better than for the other tested drying methods. Microwave vacuum drying generated rapid heat that promoted flash evaporation of the vapour in the noodles, resulting in a porous structure.

Effect of Levilactobacillus brevis TISTR 860 and Lactiplantibacillus plantarum TISTR 951 on gamma‐aminobutyric acid content in fermented rice flour and rice noodles (Kanomjeen)

SummaryThis research aimed to reduce the fermentation time of fermented rice flour for fermented rice noodles (Kanomjeen) to 24 h by adding the initial starter cultures, which are Levilactobacillus brevis TISTR 860 (LB) and Lactiplantibacillus plantarum TISTR 951 (LP) alone in rice slurry to achieve the quality and high gamma‐aminobutyric acid (GABA) content. The initial pH value of rice slurry was adjusted to 4.5 and enriched with 2% of monosodium glutamate (MSG) before fermentation. LP was able to produce lactic acid and reduced pH better than LB but produced GABA in less content. Expanding fermentation time induced decreasing in viscosity and whiteness of flour. Fermented rice noodles provided better tensile strength and elasticity. In conclusion, LB could produce GABA in the amount of 21.80 mg/100 g dry basis in 24 h with good quality.

Bio-active compounds, their antioxidant activities, and the physicochemical and pasting properties of both pigmented and non-pigmented fermented de-husked rice flour

The aim of this study was to determine the effect of both the Solid State Fermentation (SSF) technique and the use of <i>Rhizopus oligosporus</i> on the physicochemical changes of fermented de-husked rice flour. Three varieties of de-husked rice, i.e., Mentik Wangi Susu (non-pigmented), red Cempo Merah, and black Jowo Melik (pigmented) were fermented using <i>Rhizopus oligosporus.</i> Fermentation was performed at room temperature with a fermentation time of 0, 24, 48, and 72 hours. The analyzed parameters were proximate composition, bio-active compounds, and pasting profile. The results showed an increase in flour pasting profile, ash, protein, and fat content after the fermentation. The total availability of the total phenolic content (TPC) and antioxidant capacity were also increased. The highest TPC (0.37 mg GAE/g) and antioxidant capacity (1.43 mg TEAC/g) were obtained in the Jowo Melik variety at 72 hours of fermentation. In contrast, anthocyanin and carbohydrate contents decreased as fermentation time increased. The highest anthocyanin content of 0.53 mg/g (after 24-hour fermentation) was obtained in the Jowo Melik variety. In conclusion, 72-hour-fermented black rice flour (Jowo Melik) has a higher potential to be developed as a functional food.

Effect of natural fermentation on milled rice grains: Physicochemical and functional properties of rice flour

This study examined the effects of natural fermentation on rice components to understand how fermentation affects the physicochemical and functional properties of rice flour. We found that natural fermentation for 72 h had almost no effect on the structural properties of rice starch and slightly affected the protein content and composition. The charged amino acid content of rice flour decreased after fermentation, while the surface hydrophobicity increased. The surface charge of rice flour increased from −12.7 mV before fermentation to +7.06 mV after 72 h of fermentation. The reduced protein content in fermented rice flour increased the gelatinization enthalpy of rice flour to a level similar to that of starch, and enhanced starch granule expansion, resulting in an increased peak viscosity and granule breakdown, but decreased final viscosity, setback, and pasting temperature. Differences in the protein composition, surface hydrophobicity, and surface charge between fermented and non-fermented rice flour explained the greater hardness of fermented rice flour. We conclude that natural fermentation can improve the functional properties of rice flour through protein modification on the starch granule surface.

Optimizing the texture and retrogradation properties of Niangao (Rice Cake) made with naturally fermented rice flour

Abstract Niangao is prepared from polished round-grained or waxy rice flour and it is a popular and traditional steamed rice cake in China, but its preparation is different. In this study, Niangao was produced with naturally fermented rice flour and the effects of fermentation on physical properties and rheological characteristics were investigated. The results suggest that the water-holding capacity, texture, and color of the samples were significantly improved after natural fermentation, while amylose content was decreased. Additionally, fermentation had a marked effect on retarding the retrogradation of Niangao because fermented Niangao exhibited lower degree of retrogradation compared with the control. Control means Niangao which was produced by unfermented rice flour. Fermented Niangao was harder to be digested than the control was.

Effect of proteolytic bacteria on texture and colour quality of khanom-jeen, traditional Thai fermented rice noodles.

Khanom-jeen are traditional Thai fermented rice noodles with a characteristic flavour and texture. Based on their ability to hydrolyse rice proteins, five strains of proteolytic bacteria were isolated from fermented rice flour used to produce noodles in Thailand. Enterobacter ludwigii strain SK01 showed the highest degree of rice protein hydrolysis among the five strains and was selected as a starter culture for khanom-jeen production. The viable count of micro-organisms, acidity, pH, and protein and starch contents were compared throughout the fermented rice production with and without the SK01 strain. The pH of fermented rice increased on the first day of solid-state fermentation and subsequently decreased to 3·7-3·8 under both conditions. The protein content of rice significantly decreased from 80 to 18·2±0·5mgg-1 and 26±0·6mgg-1 during fermentation with and without the SK01 strain, respectively. The tensile strength, breaking length, brightness, and whiteness, which are important factors for the texture and appearance of khanom-jeen, were improved using the SK01 strain to ferment rice. The results of this laboratory-scale study indicated that the use of the proteolytic SK01 strain in fermented rice production can improve the quality of khanom-jeen noodles. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of Enterobacter ludwigii strain SK01 as a proteolytic bacterial starter culture improved the quality of khanom-jeen noodles. Compared with khanom-jeen noodles produced without E. ludwigii strain SK01, those produced using this strain showed increased tensile strength, breaking length, brightness and whiteness. These findings will be useful for the development of specific and controllable methods for producing khanom-jeen noodles with desirable texture and colour.

Study on optimization of removing cadmium by lactobacillus fermentation and its effect on physicochemical and quality properties of rice noodles

In recent years, cadmium (Cd) contaminated rice has aroused widespread concerns about the safety of rice or its products, and microbial fermentation has been proved to be a promising method for reducing Cd. The fermented rice flour can be applied as the main ingredient of rice noodles, a traditional breakfast staple in southern China. This study is aimed to screen out the optimum conditions for reducing Cd in rice noodles by mixed-Lactobacillus (LAB) fermentation, and to study its effect on the physicochemical and quality properties of rice noodles. The results revealed that the best condition of wet digestion for Cd detection in 0.5 g fermented rice noodles was following: digestive agent of 7 ml nitric acid (GR) + 3 ml perchloric acid (GR) +1 ml hydrogen peroxide (30% GR), digestion at 90 °C, 150 °C and 250 °C for 30 min, 60 min and 120 min, respectively. The optimized fermentation condition for decreasing the Cd concentration in rice flour was fermented by 8% (v/v) of mixed-LAB at 35 °C for 28 h, with the reduction of 87.6%. The mixed-LAB fermentation in rice flour was found to increase the concentrations of amylose and reducing sugar, improve its swelling power and gel properties, and produce lactic acid with the maximum amount of 612.1386 mg/L; while its rheological characteristics were significantly affected. Moreover, the quality properties of rice noodles made by the above fermented rice flour had also been improved, with higher hardness and chewiness, shorter rehydration duration, higher rehydration rate, less cooking loss and broken rate. These results showed that the fermentation by mixed-LAB can efficiently reduce excess concentration of Cd in rice flour, improve its physicochemical properties, and promote the quality property improvement of rice noodles made by it.

Optimization of lactic acid fermentation for pathogen inactivation in fecal sludge

The efficiency of lactic acid fermentation (LAF) as a pretreatment for human feces was investigated in laboratory-scale experiments that lasted for 3 weeks. The sanitization effect of LAF on fecal sludge (FS) was conducted in triplicate. This study used three materials, namely, lactobacillus of lactic acid bacteria, fermented cassava flour, and fermented rice flour, which were known to enhance the production of lactic acid. Each material was mixed in three different reactors at equal ratio with raw FS (i.e., 1:1 v/w, w/w, and w/w). The pH decline rate, lactic acid production rate, and fecal coliform suppression degree were monitored over the period of the treatment process as parameters to evaluate the efficiency of various LAF for pathogen inactivation in FS. Results showed that only fermented rice flour was able to completely inactivate the indicator organism (fecal coliform) at the end of fermentation. Final plate counts of 8.6 × 108 CFU/100 mL, 2.4 × 108 CFU/100 mL, and zero (0) were achieved from lactobacillus, fermented cassava flour, and fermented rice flour treatment processes, respectively. The final pH from the reactors that contained lactobacillus and FS, cassava flour and FS, and fermented rice flour and FS were 5.5, 8, and 3.9, respectively. This study revealed that not all LAF materials can effectively suppress pathogens in FS. The results serve as the foundation in developing an effective, cheap, and easy to use LAF on FS pretreatment for pathogen inactivation.

Locally produced lactic acid bacteria for pathogen inactivation and odor control in fecal sludge.

Providing safe fecal sludge (FS) sanitation has remained an important goal of global communities because of the high risks imposed on human health of the exposure to un-sanitized FS. This study used lactic acid fermentation as a pre-treatment technology to evaluate the sanitization effect of lactic acid bacteria (LAB) on FS. A combination of fermented rice flour and brown sugar was used as the medium to prepare LAB, and fecal coliforms were used as the indicator organisms. The addition of a LAB suspension grown in fermented rice flour and brown sugar to FS was studied to evaluate the survival of fecal coliforms. The pH decreased during ongoing lactic acid fermentation after the addition of the LAB suspension. The results revealed that fecal coliforms in reactors containing 1:1 and 2:1 w/w of FS and LAB suspension decreased to half of the initial concentration within seven days of the treatment process in comparison with that of the control reactor. Viable plate counts of 0.6 × 108, 0.9 × 108, and 2.4 × 108 CFU/100 mL were recorded from reactors 1:1, 2:1, and the control, respectively. The total elimination of the fecal coliforms below the detection limit (<3 log 10 CFU/100 mL) was observed in both reactors after 15–17 days, whereas the number of fecal coliforms remained at 2.3 × 108 CFU/100 mL in the control reactor. The fecal coliforms were eliminated because of the acidification caused by the LAB during the incubation time. The final pH in the treatment reactors 1:1 and 2:1 was 3.7 and 3.9. While the final pH in the control reactor was 7.91. The results revealed that the bacterial pathogens in FS can be completely eliminated through a low-cost technique and a simple lactic acid fermentation process.

Microbial Vitality of Probiotic Milks Supplemented With Cereal or Pseudocereal Grain Flours

&lt;p&gt;Probiotic products containing &lt;em&gt;Lactobacillus rhamnosus&lt;/em&gt; GR-1 have been shown to help decrease the risk of urogenital infections, delay the decline of CD4 lymphocytes in patients with human immunodeficiency virus, and survive in the intestinal tract without stimulating immune or inflammatory responses. Cereal and pseudocereal grains can act as prebiotic agents and could be an economical way of improving the nutritional value, functional qualities, and overall health benefits of probiotic products. The purpose of this study was to measure the growth and survival of &lt;em&gt;L. rhamnosus&lt;/em&gt; GR-1 in fermented probiotic skim milk supplemented with a grain flour over a 28-day storage period. The objective was to determine if supplementation of the grain flours would have a positive effect on the microbial vitality of &lt;em&gt;L. rhamnosus&lt;/em&gt; GR-1 in the final product and during storage. Five probiotic skim milk samples supplemented with a grain flour were prepared: oat (3% weight to volume ratio), lentil (3% w/v), rice (3% w/v), barley (3% w/v), and quinoa (3% w/v) along with one control probiotic skim milk sample. Results showed that the oat, rice, barley and quinoa flours supported the growth of &lt;em&gt;L. rhamnosus&lt;/em&gt; GR-1 at viable levels (10&lt;sup&gt;8&lt;/sup&gt;CFU/mL) during the first 14 days of storage; however, only skim milk supplemented with rice flour sustained the growth over the 28-day storage period. Future studies should conduct a sensory evaluation of this fermented probiotic rice flour milk as well as study rice milk inoculated with probiotics to produce a dairy-free and possible gluten-free product.&lt;/p&gt;

Quality Characteristics of Korean Wheat Bread prepared with Naturally Fermented Blueberry-Rice Starter and Purple Rice Flour

This study investigated quality characteristics of pan breads prepared with 0, 10, 20, 30 and 40% purple rice flour and naturally fermented blueberry-rice starters. RVA (Rapid Visco Analyzer) analysis showed that wheat flour retrogradation was not retarded by addition of purple rice flour. Using amylography, gelatinization tem. perature of purple rice flour samples was higher than that of the control, whereas maximum viscosity temperature. and maximum viscosity of purple rice flour samples were lower than those of the control. Weights of pan breads containing purple rice flour were lower than that of the control, whereas volume, specific volume and baking loss rate were higher than those of the control. The anthocyanin contents and antioxidative activites as measured by DPPH radical scavenging activity of breads increased as the concentration of purple rice flour increased. The moisture content of pan breads containing purple rice flour decreased as storage time increased. The pH of breads containing purple rice flour was higher than that of the control. Color L value decreased, whereas a and b values increased significantly, as storage time increased. In texture analyzer measurement, hardness of breads containing purple rice flour significantly increased as storage time increased. Breads containing 10∼20% purple rice flour showed acceptable sensory properties, such as mouth feel, appearance, flavor, texture, taste and overall acceptability.

Physicochemical and functional properties of yeast fermented brown rice flour.

In the current study, effects of fermentation on physicochemical and functional properties of brown rice flour (BRF) were investigated. Fermentation conditions were optimized using response surface methodology to achieve moderate acidity (pH5-6), specifically pH5.5 of brown rice batter with time, temperature and yeast concentration as the independent variables. The results indicated that brown rice batter was well fermented to maintain pH5.5 at optimum conditions of 32°C for 6.26h using 1% yeast concentration. Fermentation at moderate acidity significantly increased the levels of protein, total ash, insoluble fiber, soluble fibre, minerals, phenolics, antioxidants, resistant starch, riboflavin, pyridoxine, nicotinic acid, γ-tocotrienol, and δ-tocotrienol. However, it reduced the contents of γ-oryzanol, γ-tocopherol, α-tocopherol, phytic acid, amylose and total starch. Foaming capacity, foaming stability, oil holding capacity, gelatinization temperatures, enthalpy and whiteness of BRF were increased after fermentation. In contrast, its swelling power, water solubility index, hot paste viscosity, breakdown, and setback significantly decreased. Microstructure of BRF was also influenced, where its starch granules released from its enclosed structure after fermentation. This investigation shows evidence that yeast fermentation modified the functionality of BRF and can be used as a functional food ingredient.

Optimization of Fermentation Process on the GABA Content and Quality of Fermented Rice Flour and Dry Fermented Rice Noodles

This research aimed to investigate which process of fermentation can yield high levels of γ-aminobutyric acid (GABA) in fermented rice flour. Six methods were thus selected. It was found that process number 5 (fermentation of rice in water followed by fermentation of flour in semimoist state) yielded the highest GABA content of 25.63 mg/100 g dry matter. To optimize the fermentation process of flour, the control of fermentation of rice in water at temperature of 30C for 3 days was fixed and the fermentation of flour at different temperatures and times was varied. An experimental design by response surface method to optimize the fermentation of flour at temperature range of 28–42C for 0.2–6 days to increase the GABA content was conducted. Fermentation at temperature of 35C for 3 days yielded the highest GABA content of 36.82 mg/100 g dry matter. Practical Applications The optimization of the fermentation process to yield highest GABA (γ-aminobutyric acid) content in fermented rice flour and noodles was performed for commercial application.

백년초 및 녹차 가루 첨가 연근 부각의 지질저하 기능성

본 연구는 한국 전통부각 제조방법을 이용하여 부각을 부식으로뿐만 아니라 스낵의 용도로도 사용할 수 있게 개발하고자 하였다. 부각 제조가 상대적으로 간편하며 원료 자체의 색상이 거의 없는 연근을 선정하여 여기에 빨강, 녹색 그리고 노란색을 낼 수 있도록 천연 기능성 색소 소재로 백년초, 녹차 그리고 치자 가루를 사용하였다. 이들 기능성 색소 재료를 삭힌 찹쌀풀 제조 후 첨가하여 다양한 부각을 만들고 이를 말린 후 생 참기름에 튀겨 동맥경화식이에 10%가 되도록 첨가하여 LDLr<SUP>-/-</SUP> 마우스에 10주간 섭취시켜 지질저하기능성을 비교하였다. 실험군은 동맥경화유발식이를 섭취한 wild type mice 대조군(WC), LDLr<SUP>-/-</SUP> mice 대조군(CON), 그리고 동맥경화식이에 다양한 연근부각을 첨가한 연근부각군(LRB), 백년초연근부각군(OFB), 녹차연근부각군(GTB), 그리고 치자연근부각군(GFB)의 총 7군이었다. 부각의 효과를 비교하기 위하여 제한식이를 실시하였다. CON의 혈중 지질 농도는 WC에 비해 유의적으로 높았으며, LRB의 혈중 TG, TC 그리고 LDL-C 농도는 CON에 비해 유의적으로 낮았다(P<0.05). 기능성 색소 재료 첨가에 따른 지질저하 기능성을 살펴보았을 때 OFB와 GTB군의 혈중 TG, TC 그리고 LDL-C 농도가 LRB군에 비해 유의적으로 낮았다(P<0.05). 간의 지방산 합성 효소인 FAS와 콜레스테롤 합성 효소인 HMGCR의 발현 역시 OFB와 GTB군에서 LRB군에 비해 유의적 낮아(P<0.05) 혈중 지질 농도 결과와 일치하였다. 그러나 GFB군의 혈중 지질 농도는 LRB군보다 낮았으나 유의적인 차이를 보이지 않았고, FAS 및 HMGCR 발현 역시 유의적인 차이를 보이지 않았다. FAS 및 HMGCR의 mRNA 발현을 조절하는 전사인자인 SREBP-1과 2의 발현을 살펴보았을 때, OFB군과 GTB군은 LRB군에 비해 각각 유의적으로 낮았으나(P<0.05) GFB군에서는 발현 정도가 낮기는 하였으나 유의적이지 않았다. 이상의 결과로부터 백년초와 녹차 가루를 첨가하여 제조한 연근부각은 LDLr<SUP>-/-</SUP>마우스의 간에서 지방산과 콜레스테롤의 생합성 억제를 통해 혈중 지질의 농도를 낮추는 효과가 있음을 확인하였다.

Fermented Brown Rice Flour as Functional Food Ingredient.

As fermentation could reduce the negative effects of bran on final cereal products, the utilization of whole-cereal flour is recommended, such as brown rice flour as a functional food ingredient. Therefore, this study aimed to investigate the effect of fermented brown rice flour on white rice flour, white rice batter and its steamed bread qualities. Brown rice batter was fermented using commercial baker’s yeast (Eagle brand) according to the optimum conditions for moderate acidity (pH 5.5) to obtain fermented brown rice flour (FBRF). The FBRF was added to white rice flour at 0%, 10%, 20%, 30%, 40% and 50% levels to prepare steamed rice bread. Based on the sensory evaluation test, steamed rice bread containing 40% FBRF had the highest overall acceptability score. Thus, pasting properties of the composite rice flour, rheological properties of its batter, volume and texture properties of its steamed bread were determined. The results showed that peak viscosity of the rice flour containing 40% FBRF was significantly increased, whereas its breakdown, final viscosity and setback significantly decreased. Viscous, elastic and complex moduli of the batter having 40% FBRF were also significantly reduced. However, volume, specific volume, chewiness, resilience and cohesiveness of its steamed bread were significantly increased, while hardness and springiness significantly reduced in comparison to the control. These results established the effectiveness of yeast fermentation in reducing the detrimental effects of bran on the sensory properties of steamed white rice bread and encourage the usage of brown rice flour to enhance the quality of rice products.

김치유산균(Weissella koreensis HO20, Weissella kimchii HO22)으로 발효한 쌀가루의 이화학적 특성 및 이를 이용한 절편의 제조

Demand for a rice cake, a popular traditional food in Korea, is rising, but its industrial-scale production is extremely difficult due to its short shelf-life caused by starch retrogradation and microbial spoilage. By means of the sourdough fermentation technique, we attempt to develop rice cakes with a longer shelf-life. Heterofermentative lactic acid bacteria (Weissella koreensis HO20, Weissella kimchii HO22) isolated from kimchi were used to ferment wet-milled rice flour for their abilities to produce exopolysaccharides and to inhibit the microbial spoilage of rice cakes. After 24 hr of fermentation at <TEX>$25^{\circ}C$</TEX>, viable cell counts in rice dough increased from <TEX>$10^6$</TEX> CFU/g to <TEX>$10^8$</TEX> CFU/g and total titratable acidity increased from 0.05% to 0.20%, whereas pH decreased from 6.5 to 5.1. Fermented rice flour showed significantly lower peak, trough, and final viscosities as well as breakdown and setback viscosities measured by rapid viscoanalyzer. Both lactic acid bacteria showed in vitro antifungal activity against Penicillium crustosum isolated from rice cakes. The antifungal activity remained constant after the treatments with heat, proteinase K and trypsin, but fell significantly by increase of pH. Rice cakes made of fermented rice flour were found to retard mycelial growth of P. crustosum. The degree of retrogradation as measured by the hardness of the rice cake was significantly reduced by the use of fermented rice flour. The results suggest that use of fermented rice flour has a beneficial role in retarding starch retrogradation and in preventing fungal growth, hence extending the shelf-life of rice cakes.

Response of sheep fed on concentrate containing feather meal and supplemented with mineral Chromium

A study was conducted to evaluate the effect of substitution of protein concentrate with feather meal supplemented with organic chromium mineral on performance of lambs. Twenty five male lambs were fed basal feed of fresh chopped king grass ad libitum and were allotted to either one of five different supplements (five dietary treatments): Control (C); 10% of protein in concentrate was substituted by feather meal (FM); 10% of protein in concentrate was substituted by feather meal supplemented with Cr yeast at 1.5 mg (FMCrOrg); 10% of protein in concentrate was substituted by feather meal supplemented with Cr inorganic which equal to the amount of Cr bound in yeast (FMCr); Concentrate control supplemented with 1.5 mg Cr yeast (CCrOrg). Cr-organic was synthesized by incorporating CrCl3 in fermented rice flour by Rhizopus sp. The mineral is mixed with feather meal as a mineral carrier. Sheep in all treatments received iso protein concentrate. Parameters observed were body weight change, feed consumption and nutrient digestibility. Results shows that there was no significant effect of diet treatments on average daily gain (ADG), dry matter consumption and feed conversion, with the average value of 75.4 gr/day; 74.9 g/BW 0.75 and 9.9 respectively, However diet treatment of organic chromium and protein substitution with feather meal (FMCrOrg) showed tendency of having higher ADG (83.57 g/h/d). Average nutrient digestibility of dry matter, organic matter and NDF were 68.7; 69.6 and 60.9%, respectively. However NDF digestibility of FMCrOrg tended to be higher than other treatment (67.0%). It is concluded that partial substitution of protein concentrate by feather meal and 1.5 mg Cr-organic supplementation did not affect sheep performance. Key Words : Chromium, Sheep, Feather Meal, Supplementation