Potatoes

We investigate pricing and demand issues for four fresh potato categories (russet, red, white, and minor colored), organic fresh potatoes, and two processed potato categories (frozen/refrigerated and dehydrated) using a nonlinear generalized almost ideal demand system (GAIDS) that is closed under unit scaling (CUUS). We identify five major findings. First, we found little evidence for potato demand differences among the four U.S. regions in our study (east, west, north, and south). Second, increased consumer preferences for organic food consumption have caused price declines for red, russet and minor colored potatoes while organic potato prices rose significantly. Third, white potatoes emerged from the study as apparently the non-organic category most able to compete in an increasingly organicallyoriented market. Fourth, potatoes as an aggregate commodity are inferior good, with perhaps the exception being the minor colored potatoes. Fifth, the potato market competes with other carbohydrate groups. In particular, we find strong statistical support that lower bread or frozen vegetables prices implying reduced system expenditures on potatoes and for dehydrated potato demand being sensitive to competing carbohydrate prices.

Kulit kentang mengandung banyak serat tidak larut air, yang dapat menstimulasi kerja saluran pencernaan dan membuat buang air besar lebih teratur. Penelitian ini bertujuan untuk mengetahui bagaimana pengaruh penambahan tepung Kulit kentang (Solanum tuberosum) terhadap pakan puyuh terhadap berat karkas dan Persentase karkas sebagai pakan alternatif dengan menggunakan metode rancangan acak kelompok (RAK) dengan empat perlakuan lima ulangan P0 : Tanpa Perlakuan Kontrol 0%, P1 Tepung kulit kentang (Solanum tuberosum) 3% dalam pakan, P2 : Tepung kulit kentang (Solanum tuberosum) 6% dalam pakan, P3 : Tepung kulit kentang (Solanum tuberosum) 9% dalam pakan. Hasil penelitian ini menunjukkan bahwa penambahan tepung kulit kentang (Solanum tuberosum) tidak berpengaruh nyata (P>0,05) terhadap berat karkas dan persentase karkas puyuh. Rataan berat karkas yaitu, P0 (112,7 gr/ekor), P1 (112.96 gr/ekor), P2 116.1 gr/ekor) dan P3 (112,34 gr/ekor) dan rataan persentase karkas yaitu, P0 (64,946 gr/ekor), P1 (65.3704 gr/ekor), P2 (69, 396 gr/ekor), dan P3 (69, 644 gr/ekor). Adapun perlakuan terbaik pada berat karkas yaitu pada perlakuan P2 dengan penambahan tepung kulit kentang (Solanum tuberosum) sebanyak 6% dan persentase karkas yaitu pada perlakuan p3

Climate change and variability has hampered global agricultural growth and is anticipated to have a notable impact on crop production owing to the high reliance of agricultural activities on weather. The study examined impact of climate variability on production of major food crops (maize, beans and Irish potatoes) in Kieni West sub-County, Kenya. Mixed methods research design was used. Pearson’s coefficient of correlation (r) was used to assess the relationship between climate variables and the major food crops. Multiple Linear Regression (MLR) was employed to assess the effect of rainfall and temperature variability on major food crops. Analysis of quantitative data was done using descriptive and inferential statistics while analysis of qualitative data was done thematically. Data presentation was by use of figures, tables and verbatim quotes. Correlation results revealed a positive relationship between rainfall and bean (r = 0.46) and maize production (r = 0.33) and a negative relationship between rainfall and Irish potatoes production (r = -0.056). A negative relationship between maximum temperatures and production of bean (r = -0.89) and maize (r = -0.56) was observed while a positive relationship between maximum temperatures and production of Irish potatoes (r = 0.02) was reported. Also, correlation results revealed a negative relationship between minimum temperatures and production of maize (r = -0.35), beans (r = -0.43) and Irish potatoes (r = -0.38). Coefficient of Determination (R2) value of 0.11, 0.18, 0.003 for maize, beans and Irish potatoes respectively against rainfall was reported. R2 values of 0.32, 0.80 and 0.00 was reported for maize, beans and Irish potatoes respectively against maximum temperatures while R2 values of 0.12, 0.18 and 0.14 was reported for maize, beans and Irish potatoes respectively against minimum temperatures. The study concludes that climate variability had differential impacts on production of maize, beans and Irish potatoes in the study area.

We assess consumer demand for traditional fresh potatoes and processed potato products and willingness to pay for new experimental low-acrylamide and sulfite-free potato products. Demand for fresh potatoes, potato chips, and fries is unaffected by household income or education, but demand for chips and fries is affected by consumer age and exercise habits. Subjects display increased willingness to pay for new potato products after receiving a private company perspective about the technology and risks associated with exposure to acrylamide, a carcinogen, in fried conventional potatoes and a new product, potato dices. We find that consumers are willing to pay for enhanced food safety in fresh potato products achieved using biotechnology.

Potato production in Rwanda is constantly increasing and represents an important food and cash source for farmers. The potato crop together with maize, wheat, rice, beans and cassava is one of the six priorities crops on which the Crop intensification Program(CIP) is focusing since 2007. Its production is mainly located at high altitudes in the Northern and Western provinces. The Nyabihu, Musanze, Rubavu and Burera districts, due to their favorableclimatic conditions, are the 4 most productive districts,accountingforabout 60% of the national potato production. However, because of the low quality seed use by farmers andlow soilhealth, yields remain low with 11.6 t/ha. The aim of the study was to understand the current situation ofthe formal and informal potato seed supply systemin Rwanda.The study was conductedin the Nyabihu, Musanze, Rubavu and Burera districts from the end of June to the end of September 2016. In order to gather agronomic and socio-economic information,qualitative and quantitative data were collected using 3 social science instruments: formal-informal interviews and expert interviews. Currently, the private sector is the principal actor involved in mini-tubersproduction having a market share of 71%,while the public one has a 29% share. The actual mini-tubersproduction could cover between 13% to30% of the actual Rwandan national demand. However, due to a potato seed leak along the certification process and to a lack of actors who multiplylower seed categories into upper ones, the same figure is not reflected into the actual production of certified seed, which represents5% of the national required demand. Potato cultivation representsthe largest household income source for the sectors with the highest potatoes production levels in the region.In fact, it generates57% of the average gross income per yearper household, which is equal to 621,750 FRw (731 USD). Farmers obtain potato seed from four main sources: his/her own harvest, other farmers, the local markets and the formal seed sector. The large majority (85%) is not able to keep their own seed each season. Indeed, only15% always keeps at least a small part of their potato seed and the remaining quantity is bought off-farm when necessary. On average, the off-farm purchase is done in 57% of the cases showing a high dependency on the off-farm seed sources. Moreover, farmers use certified seed in few cases (3%), because of their unawareness of the certified seed presence in the market, the high price, the low seed availability along with the unwillingness to buy certified seed. Withthe goal of increasing the seed quality among farmers, it is recommended to introduceorextend the utilization of good agronomic practices,positive selection, plot techniques and the use of certified seed. Aiming at increasing the certified seed quantities, primarily we recommend to optimize the current multiplication process by improving the current agricultural practices and by increasing the multiplication bodies exclusively involved in the last certification phases. Only when the last phases are well organized, the mini-tubersproduction can be increased by augmenting the screen housesnumber and/or their exploitation rate. In conclusion, in order to supply Rwandan farmers with high quality seed, the formal and informal systems must be complementary and mutually dependent. The certified seed production must be combined with the development of strong and target linkages (e.g. Farmer Field School) along with the informal seed sector. The promotion of integrated-participative approaches in breeding, seed production and distribution would help increasethe complementarity between the two systems.

<p><em>This research aims to use tubers into tape products as a substitution for rice in the application of fermented biotechnological learning. The research used a type of local tubers such as sweet potato, which includes purple sweet potato (purple color), honey sweet potato (yellow color), white sweet potato (white color) and taro (Colocasia esculenta (L.) Schott.), while the control treatment used cassava (Manihot utillisima Crantz) using completely randomized research design. The tests were conducted by looking for the alcohol content and through organoleptic test (taste) as well as the appearance of the tape products by involving 20 researchers as testers. The results showed that the making of tape using tubers through fermentation process produced an average alcohol of 3.994% in honey sweet potatoes; 1.3773% in white sweet potato; 1.0576% in purple sweet potato; 1.3295% in taro and 0.59625% in cassava. The organoleptic test conducted by the panelists showed: honey sweet potato (yellow color, soft texture, sour taste, alcoholic aroma, attractive appearance); white sweet potato (white color, soft texture, sour taste, alcoholic aroma, attractive appearance); purple sweet potato (purple color, soft texture, sour taste, alcoholic aroma, attractive appearance); taro (whitecolor, rather dense texture, sour taste, mildly alcoholic aroma, ordinary appearance) and cassava (yellow color, soft texture, sour taste, alcoholic aroma, attractive appearance).</em></p>

Adaptation red potato planted on medium altitude in Bengkulu upland in order to correct land suitability classification based on criteria of land characteristics/quality. The research was conducted from July to October 2009, Kepahiang, Bengkulu located in 4 (four) experimental stations; medium altitude which located in Kelobak 525 m (up sea level, usl) and Pematang Donok, 650 m usl comparing location in Tugu Rejo 1135 m usl and Bandung Baru 1346 usl. Temperature in high altitude on Bengkulu upland was 22.3 oC in Bandung Baru and 23.5 oC in Tugu Rejo. In highland Bengkulu, land suitability class was Marginally Suitable (S3t) around Bandung Baru, while around Tugu Rejo, and medium altitude of upland Bengkulu around Kelobak and Pematang Donok with average temperature 24.8 oC categorized Permanently Non Suitable (N2t). Following the result of red potato adaptation research, there was no significantly diference among 4 (four) experimental location of potato yields in which yield of potato in Bandung Baru was 16.7 tons ha-1, Tugu Rejo was 15.5 ton ha-1, and yield of red potato in medium altitude of Bengkulu upland in Kelobak was 15.4 tons ha-1 and Pematang Donok was 19.3 tons ha-1. Based on those, temperature as a limiting factor for potato growth was the same suitable for red potato cultivation in the high and medium altitude of Bengkulu upland. Criteria of land sutability classification for potato cultivation in medium altitude of Bengkulu upland categorized N2t, Permanently Unsuitable should be corrected because of medium altitude of upland in Bengkulu high potential to develop as area for red potato cultivation. Key words: temperature, land suitability classification, red potato.

The aim of this study was to measure the effects of townspeople’s origin and acculturation on Irish potato procurement and consumption in Cameroon. It is part of the logic of developing strategies for the introduction and diversification of urban dietary practices, to reduce hunger and undernourishment in urban areas. The study plans to discover new dishes and make them culturally and traditionally acceptable following local tastes and preferences. To provide a snapshot of Irish potato city dwellers’ consumers’ characteristics, the study used a cross-sectional design. The cross-sectional sample is made up of 180 subjects, taken in each of the 12 associations; aged at least 10 years, of people, originated from Irish potato-producing areas or non, chosen in Yaoundé city, i.e. 6 associations per category. They must have spent at least 2 years in the association, that is to say, that they have experience of urban life and have stabilized their food supply mode. The main idea was that subjects from producing areas are consumers of Irish potato, following traditional food consumption patterns and concepts of food availability, while those from non-producing areas are consumers who progressively integrate and adopt potato dishes into their diets through the impact of acculturation and exposure. The first was chosen according to the sociocultural factors determining the nature of the traditional food intake in the production areas. All regions in which Irish potato was not produced were considered as non-producing areas. Results show that the predisposition of traditional food systems and preferences lead city dwellers to consume specific foods in particular ways; all the people interviewed consume Irish potato, but not at the same rate; Irish potato dishes vary and people from non-producing areas already eat some dishes like fried potato and chips at high scale. Intercultural associations could thus be an important channel for sharing Irish potato consumption information.

The present paper put forward a non-destructive detection method which combines semi-transmission hyperspectral imaging technology with manifold learning dimension reduction algorithm and least squares support vector machine (LSSVM) to recognize internal and external defects in potatoes simultaneously. Three hundred fifteen potatoes were bought in farmers market as research object, and semi-transmission hyperspectral image acquisition system was constructed to acquire the hyperspectral images of normal external defects (bud and green rind) and internal defect (hollow heart) potatoes. In order to conform to the actual production, defect part is randomly put right, side and back to the acquisition probe when the hyperspectral images of external defects potatoes are acquired. The average spectrums (390-1,040 nm) were extracted from the region of interests for spectral preprocessing. Then three kinds of manifold learning algorithm were respectively utilized to reduce the dimension of spectrum data, including supervised locally linear embedding (SLLE), locally linear embedding (LLE) and isometric mapping (ISOMAP), the low-dimensional data gotten by manifold learning algorithms is used as model input, Error Correcting Output Code (ECOC) and LSSVM were combined to develop the multi-target classification model. By comparing and analyzing results of the three models, we concluded that SLLE is the optimal manifold learning dimension reduction algorithm, and the SLLE-LSSVM model is determined to get the best recognition rate for recognizing internal and external defects potatoes. For test set data, the single recognition rate of normal, bud, green rind and hollow heart potato reached 96.83%, 86.96%, 86.96% and 95% respectively, and he hybrid recognition rate was 93.02%. The results indicate that combining the semi-transmission hyperspectral imaging technology with SLLE-LSSVM is a feasible qualitative analytical method which can simultaneously recognize the internal and external defects potatoes and also provide technical reference for rapid on-line non-destructive detecting of the internal and external defects potatoes.

An experiment was conducted in 2005/06 and 2006/07 cropping seasons on Nitosols, Acrisols and Luvisols of Western Amhara to investigate the inherent soil K status and K requirement of potato growing on ·these soils. The field experiments were conduckd in Yilmana Densa (West Gojjam Zone), Farta (South Gondar Zone) and Banja (Awi Zone) woredas. Soil samples were collected from experimental sites before planting of potato and analyzed for exchangeable K status. The treatments included in the field experiment were 6 levels of potassium fertilizer (0, 30, 60, 90, 150 and 210 kg K 2 0 ha -1 ) that were arranged in randomized complete block design with three replications. All of the K fertilizer for each treatment was band-applied at planting along and in one side of the rows at a distance of 5 cm below and 5 cm aside the seeds. Muriate of potash (KC!) was used cJS a source of K. Moreover, 81 kg N and 69 kg P 2 0 5 (recommended rates for western Arnhara) were added to all plots. This was done by applying 150 kg OAP and 58.5 kg urea at planting and side dressing 58.5 kg urea at flowering stage. Results of the experiment indicated that there was no significant increase in potato tuber number, plant height, number of main stems per plant, potato dry matter yield due to increase in K fertilizer rate on Nitosols, Acrisols and Luvisols. However, increase in K fertilizer rate significantly increased mean tuber weight and tuber yield of potato on Acrisols of Banja Woreda and. improved shelving life of potato collected from all soil types. Key words : Acrisols, Luvisols, Nitosols, Potassium, Potato

تجمع مادة خشک گیاهان ارتباط خطی با تشعشع فعال فتوسنتزی (PAR) تجمعی دارد و یکی از راههای افزایش جذب تشعشع در سیستم های زراعی استفاده از کشت مخلوط است. بعلاوه کشت مخلوط ممکن است کارایی مصرف نور گیاهان را نیز بهبود ببخشد. این مطالعه با هدف ارزیابی جذب و کارایی مصرف نور ذرت (Zea mays L.) و سیب زمینی Solanum tuberosum L.)) در کشت مخلوط انجام گرفته است. تیمارهای آزمایش شامل: تک‌کشتی ذرت (MC)، تک‌کشتی سیب‌زمینی (MP)، کشت مخلوط نواری (S)، کشت مخلوط I25، I50، I75 (به ترتیب با 25% ، 50% و 75% همپوشانی ردیف های ذرت و سیب‌زمینی در تیمار نواری) و کشت مخلوط ردیفی(R) بودند. نتایج آزمایش نشان داد که کارایی مصرف نور ذرت در تمام تیمارهای مخلوط نسبت به تک کشتی افزایش پیدا کرد، در حالیکه کارایی مصرف نور سیب زمینی در کشت مخلوط کاهش یافت. میانگین کارایی مصرف نور ذرت در طول فصل رشد از 65/2 در تیمار MC تا 27/3 گرم بر مگاژول تشعشع فعال فتوسنتزی در تیمار R و میانگین کارایی مصرف نور سیب زمینی نیز از 27/1 در تیمار R تا 47/1 گرم بر مگاژول تشعشع فعال فتوسنتزی در MP متغیر بود. در کل هر چه مخلوط از آرایش ردیفی، که فاصلة ردیف های ذرت در آن دو برابر کشت خالص بود، به سمت آرایش نواری،‌ که فاصلة ردیف های ذرت در آن مشابه تک کشتی بود، تمایل پیدا کرد (یعنی به ترتیب تیمار کشت مخلوط ردیفی، I75، I50، I25، و کشت مخلوط نواری) کارایی مصرف نور نیز به تدریج کاهش یافت، زیرا تعداد ردیف هایی که فاصلة آنها دو برابر کشت خالص شد کاهش پیدا کرد. هرچه آرایش مخلوط از نواری به سمت ردیفی تمایل پیدا کرد (یعنی به ترتیب تیمارهای I25، I50، I75، و کشت مخلوط ردیفی) تعداد ردیف های بیشتری از سیب زمینی در زیر سایة مستقیم ذرت قرار گرفت و این مسئله سبب کاهش تدریجی کارایی مصرف نور شد. جهت حصول نتایج بهتر پیشنهاد می شود که تراکم های مختلف این دو گیاه و همچنین سیستم های تأخیری مورد ارزیابی قرار بگیرد..

Leafy vegetables contain nutrients and have also antioxidant potentialities. Two of them, black nightshade and sweet potatoes leaves, were analyzed for their antioxidant capacities. Total phenolic and flavonoids were determined. The antioxidant activities determinations were on radical scavenging activities, lipid peroxidation inhibition and reducing power. The results showed that total phenolic and flavonoids content were higher in sweet potatoes leaves than in black nightshade. Indeed, sweet potatoes total phenolic and flavonoids content were respectively 933.30 ± 15.30 mg Gallic Acid Equivalent (GAE)/g of dry matter (DM) and 149.00 ± 4.00 mg Quercetin Equivalent (QE)/g DM, while that of black nightshade were 300.00 ± 5.7 mg GAE/g DM and 54.60 ± 8.30 mg QE/g DM. Consequently, sweet potatoes leaves had best antiradical activities which were characterised by their IC50 value (3.12 ± 1.42µg/ml). That of black nightshade was 163.00 ± 0.82 µg/ml. The two leafy vegetables had a lipid peroxidation inhibitory capacities upper than that of gallic acid and these inhibitory capacities were more important in sweet potatoes leaves than in black nightshade leaves. Sweet potatoes leaves IC50 was about 206.33 ± 14.05 µg/ml and that of black nightshade was 272.33 ± 21.39 µg/ml. However, reducing power in leaves was lower than that of vitamin C (the molecular reference). Antioxidant activities were high in sweet potatoes leaves. But, it could decrease after cooking process as nutrients losses are occurred during cooking.

Potato late blight, which is caused by Phytophthorainfestans (Mont.) de Bary, is a worldwide devastating disease for potato. It decreased yields of potato and caused unpredictable losses all over the world. Various simple statistical methods and forecasting models have been developed to predict and manage potato late blight. Meanwhile, there is a rising need to develop prediction models reflecting peroxidase (POD) activity, which is an important health index that varies with infection and correlated with stress resistance in plants. Thus, the aim of this research was to develop kinetic models to predict POD activity. Infection-induced changes in potato leaves stored in an artificial climate chest at 25°C were analyzed using hyperspectroscopy. Four prediction models were developed by using linear partial least squares (PLS) and nonlinear support vector machine (SVM) methods based on the full spectrum and effective wavelengths. The effective wavelengths were selected by the successive projection algorithm (SPA). In this study, the prediction model developed by means of SPA-SVM method obtained the best performance, with a Rp (correlation coefficient of prediction) value of 0.923 and a RMSEp (root mean square error of prediction) value of 24.326. Five-order kinetics models according to the prediction model were developed, and late blight disease can be predicted using this model. This study provided a theoretical basis for the prediction of latencies of late blight. Keywords: POD (peroxidase) activity, kinetic model, potato leaves, late blight, hyperspectral data, latency prediction DOI: 10.25165/j.ijabe.20191202.4574 Citation: Li Q Y, Hu Y H. Kinetic models of peroxidase activity in potato leaves infected with late blight based on hyperspectral data. Int J Agric & Biol Eng, 2019; 12(2): 160–165.

Reduction of acrylamide formation in potato chips was investigated in relation to ten pretreatments before frying. Potato slices were fried at 170 C for 5 min. Prior to frying, potato slices were soaked in one of the following solutions for 60min : (1) tap water ; (2-4) NaCl solutions (1%, 2% and 3%); (5-7) citric acid solutions (0.5 %, 1 % and 2%); (8) combined solution (NaCl 3% +0.5% citric acid); (9)tomato juice and (10) combined tomato juice(tomato juice + 1% NaCl + 0.5% citric acid). Reducing sugars and asparagine contents were determined in potato slices before frying, whereas acrylamide content was determined in the resultant fried potato chips. All studied treatments decreased both of reducing sugars and asparagene content (except tap water with asparagene), and consequently acrylamide formation. The highest reduction effects were recorded for combined tomato juice, tomato juice and combined solution of 3% NaCl+ 0.5 % citric acid, respectively. Oil uptake of fried potato only affected by NaCl treatments either separated or combined and tomato juice. In relation to sensory parameters, all studied treatments improved the sensory characteristics, with 2 exceptions: the first is the undesirable effect of citric acid treatments on taste and the second is the undesirable effect of 2% NaCl on crispiness. The highest value of over all acceptability was recorded for combined tomato juice followed by tomato juice. Keywords: Potato slices; Frying; Acrylamide; Reducing sugars; Asparagine ;oil uptake, sensory characteristics

The seed tuber size and spacing plants are important in the productivity of the potato. The objectiveof this study was to evaluate the effect of different sizes of seed tubers and plant spacing on tuberyield of potato plants cultivar Agata. The experiment was conducted in a commercial potatocrop at Guarapuava-PR, from December, 2010. The treatments were constituted of three spacingbetween plants (20, 25, and 30 cm, plot), and two different types of seed (type I and type III, subplot),arranged in a split plot design in randomized block design with three replications. The characteristicsanalyzed were: yield and total number of tubers; yield, dry matter (MS) and number of commercialtubers separated into three size classes. There was no statistically significant difference for totaland commercial yield and commercial MS among the different planting spacing and potato seedtype. There was statistically significant difference among the different planting spacing for total andcommercial number of tubers, due to higher number of small tubers (<100 g) in plants from the lowestplanting spacing. The average weight of commercial tubers of plants from potato seed type III washigher than from type I. There was no significant interaction between the different planting spacingand types of tuber seed, suggesting that the use of potato seed type III and planting spacing of 30cm provides the best cost-benefit ratio for potato growers as it minimize the use of seed potatoes inthe field and reduce the costs of crop establishment.