• Food Science and Biotechnology
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• 제15권5호
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• pp.805-813
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• 2006

The quality of frozen bread dough made with the milk proteins casein (C), whey (W), and the gums sodium alginate (A) and ${\kappa}$-carrageenan (K), was investigated to develop methods to suppress the deterioration of the frozen dough quality. The control had a lower dough volume than dough with additives during freeze-thaw cycles. In bread stored at $5^{\circ}C$, the moisture content of bread prepared with whey plus sodium alginate (WA) decreased less than that of the control. The control also had a lower specific loaf volume than breads made with added milk proteins and gums. The hardness of the control bread and bread made with casein plus sodium alginate (CA) and whey plus ${\kappa}$-carrageenan (WK) increased during freeze-thaw cycles, although that of the control increased more than the others. There was no significant difference in sensory preference among breads with and without milk proteins and gums. Addition of CA and WA improved the baking quality by reducing the deterioration of frozen dough and retarding the staling of bread.

• 한국식품과학회지
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• 제27권5호
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• pp.783-788
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• 1995

본 연구는 동결속도 및 동결저장온도가 취반된 쌀의 이화학적 특성에 미치는 영향을 살펴보고자, 단열재를 이용하여 최대 빙결정 형성신간이 3시간, 5시간, 7시간 그리고 12시간인 동결속도로 24시간 동안 동결하였고, 동결된 시료는 각각 $-20^{\circ}C$와 $-70^{\circ}C$의 냉동고에서 3개월간 저장하여 동결저장동안에 각 시료의 노화도 그리고 조직감의 변화를 조사하였다. 동결된 쌀밥의 미세구조 및 표면구조는 빙결정을 동결치환에 의해 제거한후 scanning electron microscopy(SEM)으로 관찰하였다. 취반된 쌀의 노화도는 동결속도, 동결저장온도, 저장기간에 따라 큰 영향을 받아 최대 빙결정 형성시간이 3시간에서 12시간으로 길어짐에 따라 노화도는 14.85%에서 40.00%로 증가하였고, 동결된 쌀밥의 동결저장 중 노화도는 $-20^{\circ}C$에서 저장한 것이 $-70^{\circ}C$의 경우보다 노화된 정도로 크고, 빠른 진행을 보였다. 동결된 시료를 해동한 후의 경도는 동결시키지 않은 대조구와 비교할 때 크게 증가하였으며, 또한 동결속도가 늦어질수록 더 큰 증가를 보였다. 하지만, 3개월간 저장한 후에는 경도가 다시 감소하였다. 한편, 부착성은 대조구와 비교하여 24시간 동안 동결된 쌀밥에서는 감소하였으며 3개월간 저장한 후에는 다시 증가하는 경향을 보였다. 동결된 취반된 쌀의 빙결정의 크기는 동결속도가 늦어짐에 따라 커졌고 그 수는 상대적으로 적었다. 또한 3개월간 저장한 후에는 얼음의 재결정화에 의해 시료의 빙결정은 더욱 커져 취반된 쌀의 구조가 많이 파손되었음을 확인할 수 있었다. 결론적으로 최대빙결정형성시간을 단축하여 취반된 쌀을 동결시키는 것과 낮은 온도에서 저장하는 것이 빙결정의 형성과 성장에 따른 전분의 노화와 조직감의 변화를 억제할 수 있다고 판단되었다.

• 한국축산식품학회지
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• 제31권1호
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• pp.27-31
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• 2011

To differentiate between frozen-thawed and fresh broiler breast fillets, different methods such as optical microscopy and measurement of drip loss, pH, torrymeter and K-value were performed. A total of 10 samples of fresh and frozen-thawed breast fillets were stored in a refrigerator ($4^{\circ}C$) for 5 d. Optical microscopy of the frozen-thawed breast fillets found structural changes caused by ice crystals, which may have significantly increased drip loss compared to fresh breast fillet. The pH and K-value could not be distinguished between the two breast fillets during storage. However, the torrymeter values of the fresh and frozen-thawed breast fillets were significantly different (p<0.05). The results indicate that both optical microscopy and torrymeter measurement can be effective methods for differentiating between fresh and frozen-thawed breast fillets. However, optical microscopy may be difficult to implement in the marketplace since it requires much time and effort. Thus, the determination of the torrymeter value is the easiest and most rapid instrumental method among those tested for the differentiation of frozen-thawed chicken breast fillet from fresh one.

• 한국응용과학기술학회지
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• 제10권2호
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• pp.49-56
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• 1993

The effect of frozen storage and cooking methods on lipid oxidation in chicken meat was studied. Chicken meats were stored 0, 30, 60, 90, 120 days at $-18^{\circ}C$ and were evaluated before and after cooking. 1. The crude fat content of chicken meat is the highest thigh meat with skin in microwaving. Fat content was increased duting 30 days of frozen storage, and then after. 2. Peroxide value, acid value and TBA value was increased during the days of storage because lipid autoxidation was processed cooking and during frozen storage time. The peoxide value and acid value were higher compared to sample cooked by other methods. 3. The fluoresence units were increased with frozen storage, and initial levels of fluoresent after processing. 4. The fatty acid composition of chicken meat fats is mainly palmitic acid and oleic acid, and the effect of frozen storage and meats part is not significantly change but fatty acid significantly change according to frying that linoleic acid was increased during frozen time. From all the results obtained in this study it can be conclude that lipid autoxidation of the chicken meat frozen storage at $18^{\circ}C$ was consistantly processed, and breast meat oxidation was increased than thigh meat because chicken breast meat include many polyunsaturated fatty acid. Frying was significantly increased highest than other cooking methods.

• 기술사
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• 제33권5호
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• pp.77-82
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• 2000

In this study, effect of freezing and cryogenic crushing on physico-chemical characteristics of sardine, pollack and sqiud representative for domestic frozen fishery products was investigated and some product using them was tried to be prepared. Dehead and viscerated, washed fishes were subjection to freezing without air circulation and liquid N2 gas at -20$\^{C}$,-40$\^{C}$ and -80$\^{C}$, and then frozen fishes were crushed by hammermill, masscolloider and the product was stored added with anti-freeze such as sorbitol, phosphates, starch and egg Powder, qualify of frozen squid surimi was not changes during 70 days at below -20$\^{C}$ . The results of quality characteristics and sensory evaluation of patties and nugget which made from shattered squid and pollack were similar to commercial products in flavor, color and texture, but sardine meat was inferior to commercial products in flavor and color.

• 한국식품과학회지
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• 제39권6호
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• pp.663-668
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• 2007

본 연구에서 12개월 동안 미생물 정량시험을 통해 감자의 미생물학적인 안전성을 평가하였고 영양성분 및 일반성분 분석에 의한 영양적, 물성적인 평가를 실시하였다. 미생물학적 품질변화 평가에서 상온 냉장 저장 감자의 총호기성균(total aerobic bacteria)은 24주(6개월) 동안 큰 변화를 보이지 않았다. 48주(12개월) 동안 저장한 냉동저장 감자도 균수의 변화를 보이지 않았다. 생감자는 초기 총균수가 $5.3\;\log_{10}\;CFU/g$이며 물 세척 시 약 90%(1 log) 감소하여 $4.2\;\log_{10}\;CFU/g$가 되었다. 냉동저장 감자의 초기 총균수는 약 $2\;\log_{10}\;CFU/g$ 수준(g당 약 100마리) 이였다. 반면 상온저장 감자의 진균수(yeasts and molds)는 2개월(8주)까지 증가하다가(최대치: $3.22\;\log_{10}\;CFU/g$) 그 이후부터 감소 추세를 보였고 냉장저장 감자도 12주차 때, 최대치 $2.80\;\log_{10}\;CFU/g$를 보인 후 감소 추세를 보였다. 냉동저장 감자는 원 제품부터 진균이 검출되지 않았으며 6개월(24주차)가지 불검출 상태를 유지하다가 그 이후부터 효모만 약 $1.5\;\log_{10}\;CFU/g$ 수준까지 증가하였다. 영양학적 품질변화 평가에서는 수분, 지방, 당, vitamin C, $B_1$, $B_2$의 함량 변화를 분석하였다. 상온 냉장저장 감자는 2개월(8주)간 수분함량이 다소 감소하는 경향을 보였으나 통계적으로 유의차는 없었다. 냉동저장 감자(whole potato)는 상온 냉장 저장감자(80% 전후)에 비하여 수분함량이 다소 낮았으며(60% 전후) 저장시 변화를 보이지 않았다. Frozen shoe string potato를 제외한 나머지 상온, 냉장, 냉동저장 감자에서는 지방함량이 0.002-0.01%로 거의 검출되지 않았다. Frozen shoe string potato에서는 유지가 검출되었으며, 4주차까지 다소 감소하다가 그 후 일정하게 유지되었다. 상온저장 감자의 당 함량은 저장 4주차까지 증가하다가 그 후 급격히 감소하였고, 냉장저장 감자의 당 변화량은 상온저장 감자보다 작았지만 이와 유사한 경향을 보였다. 냉동저장 감자는 12개월간 당 함량이 조금씩 감소하였으나 상온, 냉장저장 감자에 비해 변화량이 크지 않은 것으로 확인되었다. 생감자의 vitamin C 함량은 가공된 냉동감자보다 높은 것으로 나타났다. 상온 냉장저장 감자의 vitamin C 함량은 4주차 이후부터 급격한 감소를 보였으나 냉동저장 감자의 경우 더욱 서서히 감소하였다. Vitamin C와 같이 생감자의 vitamin $B_1$, $B_2$, 함량은 가공된 냉동감자보다 높은 것으로 나타났다. 상온 냉장저장 감자의 vitamin $B_1$, $B_2$ 함량은 각각 6, 4주차 이후부터 급격한 감소를 보였으나, 냉동저장 감자의 경우 48주(12개월)저장 중 함량변화가 없었다. 물성적 품질변화 평가에서 상온 냉장저장 감자의 무게와 부피는 24주간 다소 감소하는 경향을 보였으나 통계적인 유의차는 없었다. 냉동저장 감자의 무게와 부피 변화는 48주간 전혀 없었다. 상온 냉장저장 감자의 조직의 강도(hardness)는 24주간 다소 감소하는 경향을 보였으나 냉동저장 감자는 48주간 hardness의 변화가 전혀 없었다. Frozen mashed 감자는 저장기간이 지날수록 응집력(cohesiveness)이 조금씩 떨어졌으나 다른 시료들은 전혀 변화가 없었다. 모든 시료의 저장기간 동안 색깔 변화는 없었다. 결론적으로 감자의 미생물학적, 영양학적, 물성 품질을 오래 동안 유지하기 위해서는 냉동저장이 상온이나 냉장저장보다 우수하다고 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권12호
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• pp.1703-1708
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• 2009

Deproteinization has been recognized as a prerequisite for amino acid analysis of plasma samples. For plasma stored at room temperature, delaying deproteinization for 30, 60 or 120 minutes did not result in significant changes in the mean CV (coefficient of variation), which ranged from 4.4 to 5.6%. However the mean CV of aspartic acid, ${\alpha}$-aminoadipic acid, alanine and lysine was about 10%. When the plasma was stored frozen at -20${^{\circ}C}$, the CV was increased at 0 and 120 minutes after thawing, to 12.4% (range, 4.1 to 35.3%) and 8.0% (2.5 to 30.7%), respectively. The concentrations in plasma during storage at room temperature of all the amino acids analyzed showed significant changes. In plasma stored for 30 minutes at room temperature, 17 amino acids increased in concentrations and two decreased. Extending this period to 60 or 120 minutes increased the instability as compare to the reference group. Storing plasma at -20${^{\circ}C}$ for 2 weeks resulted in significantly greater changes in the amino acid concentrations than at room temperature. On extending the storage time at room temperature, after thawing, to 30, 60, and 120 minutes, 21, 20, and all 22 amino acids respectively changed significantly (p<0.01). The present study indicates that methodological errors occur in the concentrations determined for all amino acids when plasma is left at room temperature. The storage of frozen non-deproteinized plasma accompanied more significant changes in most amino acid concentrations and thus should be avoided. Deproteinization should be performed as soon as possible after plasma collection.

• 한국축산식품학회지
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• 제43권5호
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• pp.840-858
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• 2023

This study was designed to compare the quality changes in mackerel fillets stored under different conditions by using hyperspectral imaging (HSI) techniques. Fillets packaged in vacuum were stored for six days under five different conditions: refrigerated at 4℃ (R group); iced at 5±3℃ (I group); kept at an ambient of 17±2℃ (A group); frozen at -18℃ for 24 h and thawed in a refrigerator at 4℃ for 5 h on the sampling day (FTR group); FTR thawed in tap water instead of thawing in a refrigerator (FTW group). The FTR group had the lowest total bacterial count, drip loss, 2-thiobarbituric acid reactive substances, volatile basic nitrogen, and texture profile analysis values among groups during the entire storage period (p<0.05). Scanning electron microscopy revealed that the FTR group had less damage, while the other groups had shrunken muscle tissues. HIS integrated with the partial least squares model yielded reliable and efficient results, with high R²_cv values, for several quality parameters of the mackerel fillets. Overall, the FTR group, involving freezing and thawing in a refrigerator, appears to be the most favorable option for maintaining the quality of mackerel fillets, which could be practically implemented in the industry. HSI is a suitable and effective technique for determining the quality of mackerel fillets stored under different conditions.

• 한국축산식품학회지
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• 제44권1호
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• pp.74-86
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• 2024

Eggs that have been hard-boiled are frequently used as ready-to-eat food. Refrigerated and frozen storage of hard-boiled eggs causes issues, such as customer rejection owing to textural changes. The objective of this research is to ascertain how storage temperature affects hard-boiled eggs' alteration in texture over time. Medium-sized brown shell eggs were acquired from a local market, boiled at 100℃ for 15 min, and then stored at room temperature (25℃), refrigeration (4℃), and freezing (-18℃) conditions for 0, 12, 24, and 48 h. Fourier transform infrared spectroscopy (FTIR), texture profile, visual observation using a gemological microscope, free amino acid content, and color were measured. Freezing had a substantial impact on the eggs' hardness, gumminess, chewiness, and cohesiveness (p<0.05). The FTIR spectrums confirmed the textural changes in bonds of amide A (3,271 cm^-1), amide I (1,626.2 cm^-1), amide II (1,539.0 cm^-1), C=O stretch of COO^- (1,397 cm^-1), asymmetric PO₂^- stretch (1,240 cm^-1). Microscopic images confirmed structural changes in eggs stored at -18℃. The free amino acid content was lower in fresh and frozen eggs than in the rest (p<0.05). However, there was no discernible variation in the egg white's color when eggs were kept at 4℃ (p>0.05). Salmonella spp. was found exclusively in eggs kept at room temperature. In conclusion, hard-boiled eggs did not exhibit structural or chemical changes when stored at 4℃ for up to 48 h compared to freezing and room temperature conditions.

• Journal of Pharmaceutical Investigation
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• 제35권2호
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• pp.71-74
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• 2005

The aim of this study was to analyze characteristics of the barrier function of excised porcine buccal mucosa to the test compounds, estradiol, propranolol HCI, melatonin, and mannitol with a wide range of partition coefficient values. The permeability of melatonin was measured through frozen, stored, and fresh porcine buccal mucosa to examine the impact of storage conditions on the permeability of porcine buccal mucosa. The results demonstrated that the ex vivo permeability of the porcine buccal mucosa was greater for more lipophilic solutes, which was consistent with a series of molecules transported by passive transepithelial diffusion. The melatonin permeation profiles through frozen, stored, and fresh mucosa illustrated that damage was incurred by the freezing process of the mucosal tissue, leading to loss of the barrier function and thereby an increased permeation coefficient. It can be observed that the influence of compound lipophilicity on the association of the compounds with buccal mucosa was clear. The relationship between permeation coefficient and Log P values for the four compounds investigated demonstrated a proportional relationship, further confirming the importance of the lipophilicity of a compound to permeate the buccal mucosa. These results showed that the ex vivo porcine buccal mucosa model is a suitable tool to screen oral mucosal permeability.