Physicochemical,microbial, and sensory evaluation of cook-chilled Korean traditional rice cake (<Emphasis Type="Italic">Backseolgi</Emphasis>) during storage via various packaging methods

Backseolgi is a Korean traditional rice cake, which is prepared by steaming the rice flour. After cook-chilling processing, backseolgi samples packaged by a modified atmosphere package (MAP), top sealing package (TSP), and linear low density-polyethylene package (LDPA; control) were evaluated in regard to microbial safety and sensory characteristics during storage. During storage at 30°C, the cell numbers of aerobic, psychrophilic, and anaerobic bacteria for the MAP sample increased to below 2 log CFU/g for 10 days, whereas the control and TSP samples increased more than 5.0 log CFU/g after 4 days. After 50 days of storage at 3°C, the cell numbers in the MAP sample were below 1.0 log CFU/g, whereas they were approximately 3.0 log CFU/g in the control and TSP samples. In the case of the sensory evaluation, the MAP sample score was above 5.0, whereas the scores of the CON and TSP samples were 1.0. As a result, MAP was identified as the most effective packaging method for increasing microbial safety while maintaining the sensory characteristics of the cook-chilled backseolgi.     

Effects of cross-linked resistant rice starch on the quality of Korean traditional rice cake

Jeolpyeon, the Korean traditional rice cake, was prepared from the newly developed dry rice flour with 10 and 20% cross-linked resistant starch (RS4) to improve sanitation during processing and to enrich the functional properties of dietary fiber. The rice flour was prepared from white rice ‘Chuchungbyeo’ through soaking, drying and milling using a pin mill with a built-in 120 mesh sieve. The total dietary fiber contents were 44.97% for RS4, 3.57% for rice cake, 7.78 and 11.35% for 10 and 20% RS4 added jeolpyeon, respectively. With an increase in RS4 content, the swelling power, solubility, water binding capacity, and all pasting viscosities decreased, while lightness increased. Cohesiveness and resilience in the 10% RS4 added jeolpyeon was higher than those in the control. The preference test showed that the color and overall quality increased with the addition of RS4 and overall quality was the highest in the 10% RS4 added jeolpyeon.     

Effects of vacuum,modified atmospheres and storage temperature on the microbial flora of packaged beef

The flora growing on beef stored in vacuum and 100% CO₂at 2 or 6°C (experiment 1) and in vacuum and different mixtures of CO₂and N₂at −1 or 2°C (experiment 2) was determined in two separate experiments. Both a high concentration of CO₂and a low storage temperature inhibited bacterial growth, especially of the spoilage bacteria pseudomonads andBrochothrix thermosphacta. No packaging conditions gave growth of coliforms. High numbers (log₈5–6) of lactic acid bacteria after storage in vacuum or gas packs, inhibited growth of pseudomonads andB. thermosphactaduring subsequent storage under retail conditions. Samples of the lactic acid bacteria obtained in experiment 2 were identified by genus-specific rRNA probes. Leuconostocs dominated in vacuum and CO₂packs at both temperatures, whereas carnobacteria dominated in N₂at −1°C.     

冷链条件下气调包装酱卤鸭肉制品货架期预测模型的建立

目的 以气调包装酱卤鸭肉制品为研究对象,在冷链温度范围内建立一套准确、高效的货架期预测模型。方法 利用选择性培养基测定不同温度下产品各微生物数量,确定4~25℃条件下产品优势腐败菌。对乳酸菌数量与感官评定值进行了回归分析确定最小腐败量Ns。分别采用修正的Gompertz方程和平方根方程建立一、二级模型,并通过预测值与实测值对比验证模型的可靠性。结果 确定了4~25℃条件下产品优势腐败菌为乳酸菌,最小腐败量Ns=6.14(lg(cfu /g))。一、二级模型拟合度均良好,三种温度下模型预测值与实际值间的差异均在30％左右,波动幅度在10%以内。结论 实现了对4~25℃内任何时间点产品剩余货架期的预测,为冷链条件下气调包装酱卤鸭肉制品品质的变化提供了理论指导。     

优势微生物组成对米发糕品质的影响

接种酵母菌和乳酸菌复合菌株或酵母菌和根霉复合菌株制作米发糕,采用动态流变仪、氨基酸自动分析仪、气相色谱-质谱仪分析米发糕的质地、滋味和气味特征,研究优势微生物组成对米发糕品质的影响,为米发糕的品质控制提供依据。结果表明:微生物组成对米发糕品质有显著影响,接种酵母菌和乳酸菌复合菌株的米浆糊化温度较低,米发糕质地较柔软,甜味和鲜味氨基酸含量较高,挥发性物质种类较丰富,其特征香气物质为苯乙醇、辛酸乙酯、癸酸乙酯和棕榈酸乙酯。大米发酵体系中酵母菌和乳酸菌的协同作用优于酵母菌和根霉,使大米淀粉、大米蛋白质的水解程度更高,产生较多的呈味氨基酸和香气物质。     

Identification of microbial flora in kefir grains produced in Turkey using PCR

Kefir grains might have different ratios and/or content of microflora according to their origin. The purpose of this study was to determine microbial flora of kefir grains produced in three regional universities in Turkey using polymerase chain reaction (PCR) and consensus sequence primers. According to the results of PCR products with the specific primers, the following were identified as the natural inhabitants of the kefir grains: Lactobacillus acidophilus, Lactobacillus helveticus, Streptococcus thermophilus, Bifidobacterium bifidum and Kluyveromyces marxianus kefir. The results of this study revealed that traditional kefir produced by using kefir grains as natural starter cultures contains lactic acid bacteria especially Lactobacillus spp. One of the sources also contained B. bifidum. This is the first record on the presence of B. bifidum in kefir grains.     

Impact of heat-moisture treatment applied to brown rice flour on the quality and digestibility characteristics of Korean rice cake

Effect of heat-moisture treatment (HMT) of brown rice flour on the quality and digestibility of Korean rice cake (jeolpyeon) was investigated. Brown rice flour with 20% moisture content was heat-moisture treated at 100–110 °C for 1–2 h, and subsequently cooled to 4 °C for 1–2 h. The lightness of HMT rice cake decreased as HMT temperature and time increased, whereas redness and yellowness increased. The hardness, springiness, and cohesiveness of HMT rice cake were much lower than those of brown rice cake. HMT of rice cake caused an increase in the resistant starch content and a decrease in the rapidly digestible starch content. In sensory evaluation, hardness of HMT rice cake was substantially lower than that of rice cake made with untreated brown rice due to retardation of retrogradation. However, the overall acceptability of HMT rice cake was lower than that of white rice cake or brown rice cake.     

Antistaling of rice starch in a gel model system and Korean rice cake: the role of wheat flour in retrogradation-retardation technology

This study focused on the mechanisms of retrogradation-retardation technology for applications in garaetteok (steamed and extruded cylinder-shaped rice cake) production. Based on the comparison of conventional and retrogradation-retardation methods, the addition of raw wheat flour was selected as a key process. The rheological properties of gelatinized rice starch pastes after treatment with raw or autoclaved wheat flour and Novamyl L were investigated. Among them, raw wheat flour and Novamyl L resulted in significantly lowered the elastic modulus. The textural properties of garaetteok treated with raw or autoclaved wheat flour were examined by texture profile analysis (TPA) during storage for 3 days at 4°C. The hardness of garaetteok made with raw wheat flour was maintained for up to three days. In contrast, autoclaved wheat flour did not affect elastic modulus or hardness. As a result, raw wheat flour effectively retards starch retrogradation through starch hydrolysis induced by amylase in wheat flour.     

Spoilage of value-added, high-oxygen modified-atmosphere packaged raw beef steaks by Leuconostoc gasicomitatum and Leuconostoc gelidum

Moisture-enhancing and marinating of meats are commonly used by the meat industry to add value to raw, retail products. Recently in Finland, certain value-added beef steak products have proven to be unusually susceptible to microbial spoilage leading to untoward quality deteriorations during producer-defined shelf-life. This study was conducted to evaluate the role of lactic acid bacteria (LAB) in the premature spoilage of value-added beef packaged under high-oxygen modified atmospheres. Spoilage was characterised by green discolouration and a buttery off-odour. The predominant LAB in eight packages of spoiled, marinated or moisture-enhanced beef steaks were identified by reference to a 16 and 23S rRNA gene restriction fragment length polymorphism pattern (ribotype) database. Leuconostoc gasicomitatum, Leuconostoc gelidum, Lactobacillus algidus, Lactobacillus sakei and Carnobacterium divergens were found to predominate in the LAB populations at numbers above 10(8) CFU/g. Inoculation of moisture-enhanced steaks with LAB strains and strain mixtures originating from the spoiled products demonstrated the spoilage potential of L. gasicomitatum and L. gelidum isolates. These two species produced green surface discolouration and buttery off-odours similar to these found in the spoiled, commercial products.     

Structural characterization of rice starch in rice cake modified by Thermus scotoductus 4-alpha-glucanotransferase (TS alpha GTase)

ABSTRACT:  Rice cake was produced with a thermostable 4-α-glucanotransferase from Thermus scotoductus (TSαGTase). Starch molecular fine structure, texture, and retrogradation for the enzymatically prepared rice cake were investigated and compared to those for control rice cake. The amylose content in TSαGTase-treated rice cakes decreased, whereas branched and linear malto-oligosaccharides ranging from maltose to maltoheptaose increased slightly. The average molecular weight of the enzyme-treated rice starch in rice cake decreased as amylopectin macromolecules were cleaved and reorganized into small amylopectin clusters. The number of shorter side chains (degree of polymerization [DP] < 9) increased, whereas the number of longer side chains (DP > 10) decreased through the disproportionation reaction of TSαGTase. After 24 h of storage at 4 °C, the enzyme-treated samples demonstrated significantly lower melting enthalpy of retrograded starch (0.4 mJ/mg) compared to that of the control (1.4 mJ/mg). The results indicated that TSαGTase treatment effectively inhibited starch retrogradation in rice cakes. It is suggested that the reduction of amylose content, the rearrangement of amylopectin, and the production of malto-oligosaccharides caused by TSαGTase treatment are responsible for the ineffective molecular reassociation of rice starch in rice cake.     

A study of the quality characteristics of frozen Korean rice cake by using different thawing methods

The characteristics of frozen rice cakes after thawing them using different methods, such as standing at room temperature (NT), running water (RWT), pan-grill (PT), steam (ST), microwave (MWT), and superheated steam thawing (SHST), were compared. Frozen rice cakes treated by MWT or SHST showed the shortest thawing time of 3 min. The MWT treatment showed the largest thawing loss, while the ST treatment showed the highest moisture content. The ST, RWT, and MWT treatments showed the highest water activity values. The NT treatment exhibited the highest hardness values, whereas the ST treatment showed the lowest values, possibly due to the adverse effects of high temperature on them. Sensory evaluation showed differences in appearance, moistness, and tenderness according to the thawing method, but there was no significant difference in overall acceptability. This study suggests that the qualities of frozen rice cakes varied depending on the different thawing methods.     

Quality of minimally processed carrots in perforation-mediated modified-atmosphere packaging (PM-MAP)

Studies were carried out to investigate the effect of PM-MAP on minimally processed carrots with different number of perforations (0, 4, 12 and control) on flexible package, stored at 2 °C temperature. The effect of PM-MAP on headspace oxygen and carbon dioxide concentration, weight loss, surface color, firmness, pH, total soluble solid, β-carotene and microbial load were evaluated. It was observed that equilibrium modified atmospheric condition of 5–7 % oxygen and 7.8 % carbon dioxide was achieved in 4 perforation pack. Whiteness index (WI) increased in all the samples from the initial value of 22.75 to a range of 30–35 within 8 days of storage. After that, it remained almost constant for all samples except for 0 perforation packs where a decreasing trend was observed. Chroma value (CV) of samples also followed similar trends like WI and reduced from initial value of 63.08 to a range of 50–55 within 8 days of storage and remained in a constant range during further storage. Firmness of carrot slices decreased to 22–24 N and 25–28 N for 4 and 12 perforation pack respectively from initial value of 30 N after 40 days of storage. Lower oxygen availability in 4 perforation pack was main reason behind lower microbial count (5.2 log₁₀ cfu/g) after 30 days of storage. Reduction of 5.52 % and 10.10 % in β-carotene content was observed in 4 and 12 perforation pack samples. Thus for PM-MAP, 150 g of carrot samples in 4 perforation packs proved to be better than other conditions.     

Anti-complementary activity of enzyme-treated traditional Korean rice wine (Makgeolli) hydrolysates

BACKGROUND: Makgeolli brewed from rice contains about 150 g kg^?1 alcohol and has a fragrance as well as an acidic and sweet taste. During the brewing process, by‐products such as rice bran and brewery cake are produced. At the end of fermentation the matured mash is transferred to a filter cloth and the Makgeolli is squeezed out from the cake, leaving the lees of the mash. These by‐products have continued to increase every year, resulting in an ecological problem. It is therefore important to develop new uses for them. The objective of this study was to use the by‐products from the brewing of Makgeolli as a valuable functional food or nutraceutical. RESULTS: The anti‐complementary activities of crude polysaccharides isolated from Cytolase hydrolysates of Makgeolli lees at concentrations of 1000 and 500 µg mL^?1 were 84.15 and 78.70% respectively. The activity of polysaccharide krestin (PSK) was 60.00% at 1000 µg mL^?1. The active polysaccharide obtained with Cytolase comprised mainly glucose and mannose (molar ratio 1.00:0.62). CONCLUSION: Glucose‐ and mannose‐rich crude polysaccharides were isolated from the Cytolase hydrolysate of Makgeolli lees. The polysaccharides retain anti‐complementary activity to enhance the immune system as a functional food or nutraceutical. Copyright © 2011 Society of Chemical Industry     

方便年糕保鲜技术

介绍了方便年糕生产环境、保鲜剂、包装方式等因素对产品保质期的影响。试验表明：年糕片在由0．1‰乳酸链球菌素、0．05‰纳他霉素、1‰山梨酸钾、75％酒精配制的pH5．0溶液中处理15min后，沥水5min，经真空包装后，产品在常温下保质期可达4个月以上。     

Production of black rice cake using ground black rice and medium-grain brown rice

Puffed rice cakes were produced from a blend of ground black rice (GBR) and medium‐grain brown rice (GMBR) by using a rice cake machine. Effects of moisture content, heating temperature and heating time on quality of the black rice cake were investigated. The specific volume of black rice cakes showed an increasing trend with increasing tempering moisture, heating temperature and heating time. The hardness of puffed black rice cake decreased as tempering moisture and heating time increased, and was influenced more by GMBR content than heating temperature. In general, the black rice cake lightness and yellowness decreased steadily with increasing GBR content, while tempering moisture, heating temperature and heating time did not significantly affect the colours of black rice cake. On the contrary, the redness increased with increasing GBR contents. The weight loss during tumbling was not found at all puffing conditions.     

方便年糕与宁波慈城年糕物性的比较研究

为比较方便年糕与传统年糕的区别,对两者的感官、质构和玻璃化温度等特性进行了研究。在相同条件下通过对2种年糕进行感官评定比较其感官属性,发现方便年糕在感官评定上总体优于传统年糕;通过质构仪的质地剖面分析比较两者在硬度、黏性、弹性、黏聚性、咀嚼性和恢复性等指标的区别,得出的结果与感官评定基本一致;用差示扫描量热仪测定两种年糕的淀粉玻璃化温度,初步揭示了方便年糕质量超过传统年糕的原因。研究结果为方便年糕的生产提供了科学依据。     

亚麻饼粕微生物脱毒工艺

采用微生物发酵法对亚麻饼粕进行脱毒。选用L9(34)正交实验,确定微生物发酵条件为:酿酒酵母Saccharomyces cerevisiae CICC 31077,接种量为3%,含水量为50%,发酵温度28℃,发酵时间72 h,在此条件下,生氰糖苷脱除率为76.91%。     

Staling of cake prepared from rice flour and sticky rice flour

MiGao, prepared from rice flour and sticky rice flour, is a kind of steam cooked Chinese cake. Staling of MiGao resulted in loss in texture and eating quality. Moisture content, water activity, texture, differential scanning calorimetry thermograms and sensory quality of MiGao, were monitored and were found to be significantly affected by cake staling when stored at room temperature for up to 5 days. The moisture content decreased after 2 days of storage and during the following days the crumb moisture content remained practically unchanged. Firmness was developed mainly during the first day of storage, remained at a similar level from day 2 to 3 and increased slightly after the third day of storage. A decrease in sensory quality and acceptability of the MiGao was observed during storage. Differential scanning calorimetry was used to follow changes of starch retrogradation in MiGao crumb. Amylopectin recrystallisation in MiGao continued to increase during storage.     

The particle size of rice flour greatly affects the structural,textural and masticatory properties of steamed rice cake (Baekseolgi)

Food Science and Biotechnology - In this study, steamed rice cakes prepared with different particle sized flour were used to investigate how the structures of rice cakes affected masticatory...     

浅谈米果的生产工艺

介绍了近年从国外引进的以米为原料生产米饼干的工艺.