This study focuses on heat-induced gelation of pea (Pisum sativum L.) proteins to assess the potential of pea protein aggregates (PPA) as novel plant-based meat alternatives. The microstructural (SEM, CLSM), mechanical (TPA analysis), and rheological properties (G', G'') of heat-induced gels at pH 2 were systematically investigated as a function of a different pea protein concentration (7.5, 10, 12.5%) and a varying heating time (1, 3, 6, 16 h). The result showed that PPA formation at higher protein concentration and heating time contributed to a homogenous and compact heat-induced gel formation. Such gel network strengthened mechanical properties in terms of high gel hardness (40 g) and elastic texture (2.7 mm springiness). For the rheological studies, the storage modulus (G') showed an increase during both the heating and cooling phases and then stabilized during the cooled-holding phase. This suggested that the formation of durable and stable gel was induced due to the decreased mobility of protein aggregates at low temperatures. Therefore, the PPA is indicated as a potential additive for enhancing the food texture quality in the plant-based meat food industry.

The sampling bag is used as a storage container for odor gas samples. It is known that the substances recovery rate of odor bags decreases during storage time, and the degree of recovery varies depending on the characteristics of the gas sample and the material of the bag. This study investigated the recovery rate of VFA (ACA, PPA, BTA, VLA) in PEA bags during storage time. In addition, a model was developed to estimate the recovery rate of each substance as a function of time. Standard gas (ACA, PPA, BTA, VLA mixed) recovery rate was used for the model development. The concentration of the compound in the bag was measured by SIFT-MS at intervals of 1 to 2 hours. The recovery rate according to the storage time was calculated as the ratio to the initial concentration. The recovery rate of each substance according to the storage period (12h, 24h, 36h, 48h) was ACA (66.2%, 62.8%, 55.6%, 52.0%), PPA (77.6%, 72.1%, 63.0%, 58.1%, 86.6%), BTA (86.6%, 81.3%, 71.6%, 66.9%), VLA (94.8%, 89.0%, 76.6%, 71.7%). The recovery rate continued to decrease over the course of 48 hours of storage time. ACA, PPA, and BTA showed the greatest decrease within the initial 12 hours, which is form of exponential decrease. Therefore, we considered a 1~3 degree polynomial regression model and a 1~2 degree exponential decay model. Each developed model was evaluated by r², RMSE, MAPE, AIC, and then a model for each substance was selected. Selected models were tested with recovery rate data from swine farm odor samples. Only the ACA model exhibited a good performance (r² = 0.76).

본 연구는 식품 부산물의 에탄올 추출물의 항산화능, 항균특성 및 첨가제로서의 기능성특성을 알아보기 위해 실시하였다. 조사대상은 카사바 부산물, 땅콩 부산물, 완두콩 부산물, 그리고 조미료 부산물이었다. 또한, 부산물 추출물 및 BHA를 첨가한 미트 패티의 저장 중 품질특성을 비교 분석하였다. 추출물 내 총 폴리페놀 및 플라보노이드 함량은 땅콩 부산물이 다른 추출물에 비해 높게 나타났다. DPPH라디칼 소거능은 땅콩 부산물 추출물에서 가장 높은 활성을 나타내었으며(p<0.05), ABTS 라디칼 소거능 및 FRAP 활성능에서는 완두콩 부산물 추출물이 가장 높은 결과를 나타내었다(p<0.05). 땅콩 부산물 추출물은 Streptococcus pneumoniae에 대해서 강한 활성을 나타내었고, 조미료 부산물 추출물은 S. aureus와 S. pneumoniae균에 대해 매우 강한 활성을 나타내었다. 미트 패티의 저장 중 지방산화 억제능은 카사바, 땅콩, 완두콩 부산물 추출물이 BHA 첨가군과 유사하게 낮은 2-thiobarbituric acid reactive substances(TBARS) 값을 나타내었다(p<0.05). 단백질 변패도 실험에서는 완두콩 부산물 추출물 처리구가 다른 시험구에 비해 유의적으로 낮은 값을 나타내었다(p<0.05). 이상의 결과, 식품부산물은 S. aureus과 E. coli 에 대해 항균활성이 우수하고, 지방산패를 억제하기 때문에 좋은 식품첨가물로서 이용이 가능할 것으로 사료된다.

The pea aphid, Acyrthosiphon pisum, requires the nutritional endosymbiont, Buchnera, for the production of essential amino acids. However, it is unclear if host plant diet that varies in essential amino acids influences aphid regulation of its nutritional symbioses. We hypothesized that aphid genes respond to host plant diet when aphids feed on their specialized (alfalfa) compared to universal host plant diet (fava), which vary in essential amino acid concentrations. Using RNA-Seq and whole genome bisulfite sequencing, we compared the gene expression profiles and DNA methylation distributions of specialized aphid cells that harbor Buchnera (bacteriocytes) when aphids feed on their specialized compared to their universal host plant diets. Our results show that bacteriocyte transcription and methylation patterns differ between host plant diets. When aphids feed on their specialized host plant, they significantly up-regulate and/or hypo-methylate key aphid genes in bacteriocytes related to the amino acid metabolism, including glutamine synthetase (GS) and the glutamine transporter ApGLNT1. Moreover, regardless of which host plant aphids feed on, we observed significant up-regulation and differential methylation of the key genes in the amino acid metabolism and the glycine/serine metabolism in aphid bacteriocytes. We suggest that the regulatory response of key symbiosis genes in bacteriocytes allows aphids to feed on a specialized host plant diet with suboptimal nitrogen concentrations.

Among several insect pests in the potato fields, Liriomyza huidobrensis, pea leafminer, is emerging as a new threat to potato plants. Adult females damage the host mesophyll cells host due to ovipositor probing. After egg hatching, the eclosing larva also damage the leaf by mining the mesophyll and causing tissue death. Despite the importance of leafminer in potato production, there is no information available regarding its resistance level to potato cultivars in Korea. Using choice test, 21 potato cultivars consisting of 11 early-maturing, 6 mid-maturing and 4 late-maturing cultivars were evaluated the resistance to pea leafminer in the greenhouse and field condition. In this test, significant differences for resistance were observed. High levels of resistance to leafminers were obtained from cvs. Namsuh, Seohong, Jayoung and Superior. These resistant cultivars might be useful in future breeding programmes.

The pea leafminer fly, Liriomyza huidobrensis Blanchard (Diptera: Agromyzidae), is an emerging pest in Korea. High population and heavy damage of this pest were observed from potato fields in the southern part of Korea in 2012. Morphological and genetic evidence confirmed the species as L. huidobrensis. The infestation was expanding throughout the country and a rich complex of parasitoid was recognized. From the exclusion study, high density infestation of leafminers reduced yield among potato varieties (Chubeak, Seohong, Goun, Dejima, and Sumi). Higher leaf damage was evident in the lower part of plants. In olfactory bioassay and feeding preference tests, leafminers choosed the Goun variety most. Given the six constant temperatures, the developmental time from egg to adult significantly decreased with increment of temperatures. From the insecticide toxicity tests, abamectin and lepimectin and spinetoram were found effective against immature stages, while cartap hydrochlorid (Neonicotinoid) was against adult insects. Overall, these studies help to pave the ways for managing this new invasive pest.

Many previous ecological studies on three major bacterial symbionts and a newly discovered symbiont PAXS (pea aphid X-type symbiont) in the pea aphid Acrythosiphon pisum have shown that these symbionts are associated with the expression of a variety of host phenotypes, including resistance to parasitoid Aphidius ervi and tolerance to heat stress. The principal role of all four symbionts “Candidatus Serratia symbiotica”, “Candidatus Hamiltonella defensa”, “Candidatus Regiella insecticola”, and PAXS is to protect aphids against abiotic stress by preserving the cells in which most of symbionts dwell and by reducing the rate of parasitism. In this experiment, we detected endosymbionts from four aphid clones by means of genomic DNA extraction, PCR with gene specific primer, and restriction enzyme cutting. The patterns of PCR and restriction enzyme cutting were all identical in the four aphid clones. In order to specifically identify the endosymbiont, we searched the sequences using BLAST. The BLAST search revealed that nucleotide sequences of the symbiont were 98% identical to Serratia entomophil. S. entomophil is also known to provide tolerance to heat stress, resistance to parasitoid wasps, and restoration of reproduction in aphids, suggesting its role in host protection.

In this study, a series of experiments were carried out to measure temporal stability of trimethylamine (TMA) in two different bag sampler types (polyvinyl fluoride bag (PVF) and polyester aluminum bag (PEA)) as a function of storage time. To this end, temporal variability of TMA was measured using its standard gas samples up to 4 days. For the purpose of comparison, storability of TMA was tested between PVF and PEA. To this end, standard gas samples were prepared at two concentration levels of 1 and 10 ppm. The results of this study indicate that the reduction of TMA levels generally increased with the extension of the storage time. Although both bag types showed moderate losses of TMA, differences between bag types (PVF and PEA) were likely to be less significant than those of concentration levels.

Phosphoprotein Enriched in Astrocytes (PEA15) is a 15kD-sized intracellular signaling protein, highly expressed in astrocytes and constitutively expressed in peripheral tissues. Recently it was found that PEA15 expression was elevated in patients suffering type 2 diabetes and suggested to be involved in the syndrome of insulin resistance. To investigate the functional role of PEA15 for the control of blood glucose level, we produced a transgenic pig over-expressing mouse PEA15 (mPEA15). As a model animal, pig has many advantages. They have a higher fecundity and a short generation time and are physiologically similar to human. Using the transgenic pig, we carried out a series of experiments to establish a link between PEA15 expression and the insulin resistance. Our results suggested that, compared with control pig, mPEA15 pig has, (1) a higher blood resistin level, (2) a lower cell membrane-embeded GLUT4 level, and (3) a lower glucose clearing ability based on oral glucose tolerance test (OGTT). When our results combined, it can be concluded that mPEA15 over-expressing pig has many symptoms of insulin resistance and these pigs will become a useful disease model to investigate diabetes mellitus in the near future.

The overexpression of Phosphoprotein Enriched in Astrocytes (PEA15) gene is commonly found in human diabetic patients. The overexpression of this gene in skeletal muscle and fat tissues have been reported to cause insulin resistance, thereby impairing insulin stimulated glucose uptake. We introduced a gene of mouse PEA15 (mPEA15) and enhanced green fluorescent protein (EGFP) into fertilized one cell pig zygotes using microinjection, and produced a piglet that showed overexpression of mPEA15 in the muscle tissues and expression of EGFP in the ear tissues and hooves. RT-PCR RFLP, southern blot and FISH analysis showed that the tissues carried the transgene. Real-time RT-PCR and western blots demonstrated that PEA15 gene was overexpressed in the various tissues and muscle tissues, respectively. These facts suggest that expression vector system is normally expressed in the trnasgenic (TG) pigs. To use as animal diseases model for type 2 diabetes, further study is necessary to confirm whether diabetes occur in these TG pigs, especially insulin resistance.

The enzyme invertase contributes to sugar unloading, pathogen defense, differentiation and development in plants. We cloned the complete cDNA of a soluble acid invertase from pea seedlings (Pisum sativum) via RT-PCR and the rapid amplification of the cDNA

본 연구는 청보리와 월동 콩과작물인 사료용 완두와의 혼파재배를 통해 사료작물로 이용하기에 적합한 작부체계로서의 혼파비율을 구명하고, 조단백질, ADF, NDF 등과 같은 사료가치와 수량을 만족하는 적정한 혼파비율을 비교 분석하기 위하여 실험을 수행하였다. 청보리와 사료용 완두를 혼파재배하였을 때 청보리의 생육특성에서 출수일과 초장은 큰 차이가 없었으며, 청보리의 경수는 사료용 완두의 혼파비율이 높을수록 감소하였지만, 사료용 완두의 개체수는 증가하였다.