Sains Malaysiana 50(12)(2021): 3593-3602

http://doi.org/10.17576/jsm-2021-5012-11

Hydro-cooling as Means to Retain Fresh Sweet Corn Ears Quality

(Penyejukan Hidro sebagai Kaedah Mengekalkan Kualiti Tongkol Jagung Manis Segar)

PHEBE DING¹* & RAJA NORHIDAYU RAJA MAT¹

¹Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia

Diserahkan: 23 Oktober 2020/ Diterima: 8 April 2021

ABSTRACT

Sweet corn ear is a highly perishable produce with short postharvest life due to its high respiration rate which depletes sugar concentration in kernel. As a result, ear loses its sweetness and quality within 1 to 2 days under room temperature. Hydro-cooling after harvest is a good practice as it can reduce the metabolism and respiration rate of the produce. Thus, the objective of this study was to determine the effectiveness of hydro-cooling in retaining quality of sweet corn ears. Freshly harvested sweet corn ears were immersed in hydro-cooler to achieve its half and seven-eighth cooling time. Pre-cooled and non-pre-cooled ears were then stored at 12±2 and 25±2 °C for 8 days and quality index, weight loss, pH, soluble solids concentration, titratable acidity and ascorbic acid of ears were evaluated at 2 days interval. The experiment was arranged in randomized complete block design with factorial arrangement (three cooling times × two storage temperatures × five storage days) and then repeated thrice. Differences between cooling time × storage temperature, cooling time × storage day, storage temperature × storage day and cooling time × storage temperature × storage day were significant on quality index of ears. Storage temperature × storage day was also significant on ears weight loss, soluble solids concentration and pH. Seven-eight cooling time and storage at 12±2 °C provide the best quality index of ears; retain higher soluble solids concentration and pH with significantly lower weight loss compared to other cooling time treatment and 25±2 °C storage temperature. In short, temperature management is crucial in manipulating sweet corn ears quality.

Keywords: Cooling time; pre-cooling; quality index; storage day; storage temperature

ABSTRAK

Tongkol jagung manis merupakan hasil mudah rosak dengan hayat lepas tuai yang pendek kerana kadar respirasinya yang tinggi menghabiskan kandungan gula di dalam biji. Oleh itu, kemanisan dan kualiti tongkol hilang dalam 1 atau 2 hari pada suhu bilik. Penyejukan hidro selepas tuai merupakan amalan bagus kerana ia dapat mengurangkan metabolisma dan kadar respirasi hasil. Oleh itu, objektif kajian ini adalah untuk menentukan keberkesanan penyejukan hidro dalam mengekalkan kualiti tongkol jagung manis. Jagung manis yang baharu dituai direndamkan ke dalam penyejuk hidro untuk mencapai masa penyejukan setengah dan tujuh-per-lapan. Kemudian, tongkol yang dipra-sejuk dan tanpa dipra-sejuk disimpan pada suhu 12±2 dan 25±2 °C selama 8 hari dan indeks kualiti, kehilangan berat, pH, kepekatan pepejal terlarut, keasidan tertitrat dan asid askorbik tongkol dinilai selang 2 hari. Uji kaji disusun dalam reka bentuk blok lengkap secara rawak dengan pengaturan faktorial (tiga masa penyejukan× dua suhu penyimpanan× lima hari penyimpanan) dan diulang sebanyak tiga kali. Perbezaan antara masa penyejukan× suhu penyimpanan, masa penyejukan× hari penyimpanan, suhu penyimpanan× hari penyimpanan dan masa penyejukan× suhu penyimpanan× hari penyimpanan adalah berkesan pada indeks kualiti tongkol. Suhu penyimpanan× hari penyimpanan juga berkesan dalam kehilangan berat, kepekatan pepejal terlarut dan pH tongkol. Tujuh-lapan masa penyejukan dan suhu penyimpanan 12±2 °C memberikan indeks kualiti tongkol yang terbaik; mengekalkan kepekatan pepejal terlarut dan pH yang lebih tinggi serta kehilangan berat yang berkesan dengan lebih rendah berbanding dengan rawatan masa penyejukan yang lain dan suhu penyimpanan 25±2 °C. Secara ringkasnya, pengurusan suhu adalah sangat penting dalam memanipulasi kualiti tongkol jagung manis.

Kata kunci: Hari penyimpanan; indeks kualiti; masa penyejukan; pra-penyejukan; suhu penyimpanan

RUJUKAN

Arendse, E., Fawole, O.A. & Opara, U.L. 2014. Influence of storage temperature and duration on postharvest physico-chemical and mechanical properties of pomegranate fruit and arils. CyTA - Journal of Food 12(4): 389-398.

Bakry, M.O., El-Shorbagy, T., El-Desuki, M., El-Behairy, U.A. & Ibrahim, H.A. 2015. Effect of some postharvest treatments on sweet corn (Zea mays var. rugosa) quality during storage. Middle East Journal of Agriculture Research 4(4): 925-931.

Bhushan, B., Pal, A., Narwal, R., Meena, V.S., Sharma, P.C. & Singh, J. 2015. Combinatorial approaches for controlling pericarp browning in litchi (Litchi chinensis) fruit. Journal of Food Science and Technology 52(9): 5418-5426.

Cortbaoui, P. 2005. Assessment of precooling technologies for sweet corn. McGill University. MS Thesis (Unpublished). 

Ding, P. & Ong, P.T. 2010. Extending ‘Kampuchea’ guava shelf-life at 27 °C using 1-methylcyclopropene. International Food Research Journal 17(3): 63-69.

Ding, P. & Syazwani, S. 2016. Physicochemical quality, antioxidant compounds and activity of MD-2 pineapple fruit at five ripening stages. International Food Research Journal 23(2): 549-555.

Garrido, Y., Tudela, J.A. & Gil, M.I. 2015. Comparison of industrial precooling systems for minimally processed baby spinach. Postharvest Biology and Technology 102: 1-8.

Henry, F.E. & Bennett, A.H. 1973. 'Hydroaircooling' vegetable products in unit loads. Transactions of the ASAE 16(4): 731-739.

Iribe-Salazar, R., Caro-Corrales, J., Hernández-Calderón, Ó., Zazueta-Niebla, J., Gutiérrez-Dorado, R., Carrazco-Escalante, M. & Vázquez-López, Y. 2015. Heat transfer during blanching and hydrocooling of broccoli florets. Journal of Food Science 80(12): E2774-E2781.

King, G.A., Henderson, K.G. & Lill, R.E. 2008. Shelf life of stored asparagus is strongly related to postharvest accumulated heat unit. Annals of Applied Biology 112(2): 329-335.

Kongwong, P., Boonyakiat, D. & Poonlarp, P. 2019. Extending the shelf life and qualities of baby cos lettuce using commercial precooling systems. Postharvest Biology and Technology 150: 60-70.

Maurer, A.R., Bentley, S. & Ormrod, D.P. 1969. Some effects of hydrocooling on sweet corn. Canadian Institute of Food Technology Journal 2(1): 3-5.

Mohamed, N.T.S., Ding, P., Jugah, K. & Hasanah, M.G. 2017. Potential of UVC germicidal irradiation in suppressing crown rot disease, improving postharvest quality and antioxidant capacity of Musa AAA ‘Berangan’ during fruit ripening. Food Science & Nutrition 5(5): 967-980.

Prusky, D. 2011. Reduction of the incidence of postharvest quality losses, and future prospects. Food Security 3(4): 463-474.

Ruslan, N.A., Man, N., Mohd Nawi, N. & Ding, P. 2013. Factors that influence the implementation of postharvest handling practices among fresh vegetable producers in selected states in Malaysia. Journal of International Food and Agribusiness Marketing 25(sup1): 87-97.

Samira, A., Woldetsadik, K. & Workneh, T.S. 2013. Postharvest quality and shelf life of some hot pepper varieties. Journal of Food Science and Technology 50(5): 842-855.

Shao, X. & Li, Y. 2011. Quality control of fresh sweet corn in controlled freezing-point storage. African Journal of Biotechnology 10(65): 14534-14542.

Siang, L.M., Ding, P. & Mahmud, T.M.M. 2019. Response of 1-methycyclopropene on postharvest quality of local soursop (Annona muricata L.). Sains Malaysiana48(3): 571-579.

Tolesa, G.N. & Workneh, T.S. 2017. Influence of storage environment, maturity stage and pre-storage disinfection treatments on tomato fruit quality during winter in KwaZulu-Natal, South Africa. Journal of Food Science and Technology 54(10): 3230-3242.

Vigneault, C., Goyette, B., Gariépy, Y., Cortbaoui, P., Charles, M.T. & Raghavan, V.G.S.  2007. Effect of ear orientations on hydrocooling performance and quality of sweet corn. Postharvest Biology and Technology 43(3): 351-357. 

Zainal, B., Ding, P., Ismail, I.S. & Saari, N. 2019. Physico-chemical and microstructural characteristics during postharvest storage of hydro-cooled rockmelon (Cucumis melo L. reticulatus cv. Glamour). Postharvest Biology and Technology 152: 89-99.

Zhang, Z., Nakano, K. & Maezawa, S. 2009. Comparison of the antioxidant enzymes of broccoli after cold or heat shock treatment at different storage temperatures. Postharvest Biology and Technology 54(2): 101-105.

*Pengarang untuk surat-menyurat; email: phebe@upm.edu.my