Volu•£ 128, Nu.IMa 4 JOHURNAL of SciE~C!~

Turrls pagasa

Balanophora fungosa Balanophora papuana ssp. fungosa Phili~pine Biodiversity

Platymantis luzonensis Platymantls citgayanensis

Platymantls sierramadrensis About the Cover

The cover presents an overall glimpse of the three articles in this issue discussing some floral and faunal species found in the Philippines. The review article of Angel C. Alcala and Walter C. Brown on Philippine platymantine frogs entitled "Philippine Frogs of the Genus Platymantis (Amphibia:Ranidae)" summarizes the currently know species assigned to the genus Platymantis. The number of species reported in this paper is 26, all of which but one are endemic to the Philippines, but more species new to science are expected to be discov­ ered as a result of field and laboratory studies being undertaken at present. The isolation and fragmentation in the past of many Philippine islands with their moist to wet tropical rain forests has been major factor influencing the differentiation of platymantine frog population into various species. Figure 1 in page 282 illustrates the morphological differentiations among the three currently recognized groups of species placed in the genus Platymantis. Baldomero M. Olivera's research manuscript entitled "The subfamily Turrinae in the Philip­ pines: The Genus Turris (Roding, 1798)" describes twelve distinct species of Tunis found in the Philippine waters, four of which are new. One of the newly described species is Turris pagasa. Pagasa, a Tagalog term for hope, seemed "appropriate for a species discovered in the closing days of the millennium, representing the hope that in the new millennium, a new generation of Philippine scientists will devote themselves to the study and conservation of our unique and threatened fauna" {quotation from the original description on pages 304 and 306 of this issue). This article is an important contribution to the understanding of the Tunis species, especially because the Philippines has the richest biodiversity of marine molluscs in the world and Philippine shell-gathering fishermen have made seashells the basis of an important industry. The research manuscript of Victor B. Amoroso entitled "The Morphology and Identity of Two Species of Balanophora in Bukidnon, Philippines" describes the detailed gross morphol­ ogy of Balanophora papuana Schltr. and B. fungosa J.R. & S. Forster leading to their identifi­ cation. The determination of the taxonomic status of the latter species has added a new record of Balanophora species of the island of Minadanao, Philippines. Since Balanophora species belong to the less known and one of the very few species of parasitic flowering plants, the article provides additional information on the richness of the Philippine floral biodiversity.

Editorial Staff Subscription Information The Philippine Journal of Science is a quarterly scientific Holly PB. Samonte publication of the Science and Technology Information Institute­ Managing Editor Department of Science and Technology {STII-DOST).

Vito M. Butardo Jr. For subscription request or inquiries, you can contact: Copy Editor Jean Dolotina Mario B. Buarao. Jr. Science and Technology information Institute Production Editor POST Complex, General Santos Avenue Bicutan, Taguig, Metro Manila, Philippines Phone: 632 838 1442 James lntia Production Assistant Authors' guide for the writing of manuscripts can be found on Virginia P. Dolotjna pages 367-369. Manuscripts can be submitted to the editorial Printing Supervisor office at the following address:

Vito M Butardo Jr Lourdes J. Cruz Graphics, Layout Editor-In-Chief c/o Marine Science Institute & Cover Design University of the Philippines Diliman 1101 Quezon City, Philippines Catherine Y Dy Phone: 632 433 2991 Marje Krjstjne Baraoidan Fax: 632 928 8799 Editorial Assistants E-mail: [email protected] I luly@msi01 .cs.upd.edu.ph Philippine Journal of Science

December 1999 ISSN 0031 - 7683 Vol. 128 No.4 PJS is a quarterly sci.,ntific publication of \he Science and Technology Information lns1itute. Department of Science and Technology (STII-DOST). Lourdes J. Cruz Editor-In-Chief University of the Philippines Dillman & National Academy of Science and Technology

Helen T. Yap Caesar Saloma Associate Editor Associate Editor University of the Philippines Diliman University of the Philippines Dillman

Editorial Board Fe Abogadie Anicia Hurtado University College London, United Kingdom SEAFDEC, Iloilo, Philippines

Alfonso M. Albano Chris Ireland Bnyn Mawr College, Pennsylvania USA University of Utah, USA

John Bennett Bienvenido 0. Juliano international Rice Research Institute, Los Banos, Philippines Philippine Rice Research Institute, Lag una, Philippines

llda Borlongan Hisato Kondoh SEAFDEC, Iloilo, Philippines Osaka University. Japan

Felixberto Buot Severino L. Koh Naval Research Laboratory, Washington D.C., USA University of Manyland, USA

Fellno Ramon A. Cagampang Amador Muriel University of Manchester, UK University of the Philippines Los Banos, Laguna, Philippmes

Josefino Comiso Baldomero Olivera NASA Goddard Space Flight Center, Maryland, USA University of Utah, USA

Benito De Lumen Eduardo A. Padlan University of California Berkeley, USA National Institutes of Health, Manyland, USA

Patrick Delmas Mary Dence Pato University College London, UK University of Saskatchewan, Canada

Sevilla D. Detera-Wadleigh Florante A. Quiocho National Institutes of Health, Manyland, USA Baylor College of Medicine, Texas, USA

Joan C. Ferrer Emilia T. Quinitio Universitat de Barcelona Marti i Franques, Barcelona, Spain SEAFDEC. Iloilo, Philippines

Danilo Fernando Corazon Santiago State University of New York. USA SEAFDEC, Rizal, Philippines

Scott Franzb!au Rosalia CM. Simmen Lousiana State University, USA University of Florida, USA

Luis Maria Garcia Oanilo A. Tagle SEAFDEC, Iloilo, Philippines National Institutes of Health, Manyland, USA

Romel Gomez Joebert D. Toledo University of Manyland, USA SEAFDEC, Iloilo, Philippines

Kelly W. Hughes Francis TS. Yu Washington State University, USA Pennsylvania State University USA Philippine Journal of Science December 1999 ISSN 0031 - 7683 Vol. 128 No. 4

Editorial Page Research Publication 279 F. Lacanilao

Review Articles Philippine Frogs of the Genus Platymantis 281 {Amphibia:Ranidae) A. C. Alcala and W. C. Brown

Pl"oduction Systems Modelling for Sawmills: 289 An Overview R. J. Me1mban and G. A. Mendoza

Research Articles The Subfamily Turrinae in the Philippines: 295 The Genus Turris B. M. Olivera

The Morphology and Identity of Two Species of 319 Balanophora in Bukidnon, Philippines V. B. Amoroso and A. C. Semitara

Varietal Effects on Properties of 331 Molded Puffed Brown-Rice Cakes B. 0. Juliano, L. T. Roferos and M. Pels

Preparation and End-functionalized Polymers 339 by Allylic Sulfide Chain Transfer and Subsequent Synthesis of Block Copolymers W. K. Busfield, C. I. Z. Holdsworth, D. T. Ouano and S. H. Thang

Antimicrobial Flavones from Coleus amboinicus 347 C. Y. Ragasa. Z. Pendon, V. Sangalang and J_ A. Rideout

An Optical Sensor for Lead Based on 353 Immobilized Dithizone E. C. Quinto and N. V. Rodriguez

Feature Article Integrating Biotechnology in the National Rice 357 R & D Agenda L. S. Sebastian and S. R. Obien

Author's Guide 367

Philippine Journal of Science RESEARCH 128 (4): 331 - 337, December 1999 ISSN 0031 - 7683 .

Varietal Effects on Properties of Molded Puffed Brown-Rice Cakes

1 1 2 Bienvenido 0. Juliano ', Leslie T. Roferos and Michael Pels

'Philippine Rice Research Institute Los Banos, 4031 College, Laguna, Philippines 2Real Foods Pty Ltd, 47 Campbell Road, St. Peters, NSW 2044, Australia

Ten types of brown rice differing in amylose content {AC) and gelatinization temperature (GT) were converted in a Lite Energy rice cake machine into molded rice cake at specific volumes of 7 and 11 mllg. Color, lnstron hardness, Rapid Visco Analyser (RVA) viscosity and differential scanning calorimetry (DSC) of the puffed cake were determined. Waxy rice types burned and failed to expand. It was determined from lnstron three-point bending and puncture tests that PSB Rc 14 cake (high­ intermediate GT, intermediate AC) was hardest and IR24 cake (low GT, low AC) was softest at a specific volume of 7 mllg. PSB Rc 14, PSB Rc 6 (low GT, high AC) and IR64 (high-intermediate GT, intermediate AC) cakes were hardest and PRJ 5 (low GT­ Iow AC) cake was softest at a specific volume of 11 mUg. Cake hardr>ess was not always similar for rice types of the same GT-AC type. Most samples were completely gelatinized as indicated by the absence of a gelatinization endotherm in DSC and very low viscosity in the RVA profiles of the rice cakes. RVA viscosity was highest for starting cold paste.

Key words: amylose content effect, gelatinization temperature effect, lnstron hardness. RVA viscosity

Molded puffed rice (ampaw) is a popular snack in (Hsieh et al. 1989, USA Rice Council 1992}. The US the Philippines (Juliano & Sakurai 1985, Villareal & retail market was US$57 million in 1987 (Hsieh et al. Juliano 1987, Carpio et al. 1990). It is prepared from 1989) and close to US$300 million in 1996 (Real non-waxy milled rice by gun-puffing at 21 ooc at a Foods Ply Ltd data). They are marketed as disc­ gauge pressure of 12-13 kg/cm2 and by molding the shaped, puffed products that are low in energy puffed rice using caramel solutton as binder and (calories) due to their low serving weight. The main sweetener. Partially flaked parboiled waxy brown rice ingredient is long-grain or medium-grain US brown (pinipig) is also gun-puffed or puffed by roasting in hot rice. Other minor ingredients S!.lch as sesame seed, oil, mixed with cooked caramel and molded. Protein millet. salt and flavoring may be added. They are content correlates negatively with expansion ratio of consumed in the US mainly as plain-flavored low­ puffed rice (Villareal & Juliano 1987). calorie snacks, (USA Rice Council 1992). Rice cakes are a relatively new ethnic snack in Puffed rice cakes are produced by a Lite Energy the United States and are derived from Australia rice cake machine based on pressure-drop method

'Corresponding aulhor: bjuliano@laguna. net with no added binder. The machine consists of two

331 B. 0. Juliano, l. T Roferos and M. Pels separate sets of electrically-heated molds into which, Amylograph runs was 45 BU for peak, 25 BU for using pneumatic air cylinders, the rice is deposited, breakdown, 30 BU for consistency and 40 BU for crushed, heated (e.g. 214"C for 7 s [Hsieh et al. setback, whereas mean standard deviation for 1990]) and then forced to expand rapidly into a small duplicate RVA runs was 3 RVU for peak, 2 RVU for chamber. The rice grains fuse together to form a breakdown, 6 RVU for consistency and 3 RVU for cake. setback (Roferos & Juliano 1997). Better cakes are produced from brown rice than from milled rice as the bran layer helps control the Preparation of rice cakes expansion and produces a better-formed cake (Real Each brown rice sample (2 kg) was frozen for 4 Foods Pty Ltd data). Quality factors of concern are days before phytosanitary certification. They were air­ appearance and/or volume, color, texture and integrity shipped to St. Peters, Australia for rice cake of the rice cakes (Huff et al. 1992 ). processing in a Grain Popper (Lite Energy) twin-head Because of the potential market for these rice model rice cake machine (Hsieh et al. 1989) under cakes in the Philippines and Asia, the effect of rice identical conditions. The standard 102 x 16 mm variety on the properties of the product was studied (diameter x thickness) cake (11 mUg specific in collaboration with Real Foods Pty Ltd. Ten aged volume, 0.09 g/mL bulk density) and the denser and brown rice samples (2 kg each} representing the crunchier 95 x 13.5 mm (diameter x thickness) cake various amylose content (AC) and gelatinization (7 mUg specific volume, 0.14 g/mL bulk density) temperature (GT) types were airshipped to Australia were prepared from the brown rice samples adjusted for puffing under identical conditions and then to 14.0-16.5% moisture content with moisture returned to Phi!Rice Los Banos for assessment. tempering for at least 6 h. The 20 batches of 20-30 rice cakes were packed in sealed plastic bags and MATERIALS AND METHODS airshipped to PhiiRice Los Bafios for evaluation.

Source and Analysis of Brown Rice Analysis of rice cakes Aged rough rice samples were obtained from the The rice cakes or rice cake powders were 1995 crops and 1996 dry season crops of the seed analyzed in duplicate for color using a Minolta production and seed health units of Phi!Rice. RD4 Chromameter CR-110 in L*a*b* mode and for waxy brown rice was obtained from Ngamchuen hardness (3-6 cakes) by a modified breaking test Kongseree, Pathumthani Rice Research Center, (Hsieh et al. 1990) using a 9.62-cm2 plunger with a Thanyaburi, Pathumthani, Thailand. Rough rice was 47-mm diam opening. A three-point bending cell 44 dehulled in a Satake THU-35 type dehusker. Brown mm apart and 62 mm wide was also used (Davis rice length and width were determined on duplicate 10 1921) on triplicate whole cake without trimming. The grains using a photoenlarger (10x). Brown rice was broken samples from the lnstron measurement were milled in a McGill miller no. 2. The milled rice was ground in a Udy cyclone mill with 40-mesh sieve. analyzed in duplicate for alkali spreading value of six From the ground sample, 3.00 g flour samples (dry­ grains (Little et al. 1958) and lnstron cooked rice weight basis) with total water adjusted to 25 g were hardness using a water-rice weight ratio of 1.2 for analyzed in duplicate for RVA-30 pasting viscosity cooking (Juliano & Villareal 1993). Milled rice was (Whalen 1996, Whalen et al. 1997). The program ground into a fluur in a Udy cyclone mill and analyzed measured culd viscosity (peak viscosity in 0-2 min at in duplicate for crude protein (N x 5.95) and apparent 30•C), peak (during 2-6 rr.in ramp to 95•C), trough amylose content (Juliano et al. 1981) and for (lowest 'Jiscosity at 6-10 min at 95°C) and final unreplicated Amylograph and Rapid Visco Analyzer viscosity on cooling at 30•C (10-11 min cooling on (RVA) pasting viscosity values (Juliano et al. 1985, [set at 30•C] and hold at 30°C to 22 min). Breakdown Juliano 1996). Both Amylograph and RVA runs started (peak minus trough at 95°C), consistency (highest at 5Q°C, heating to 95•C and cooling to 500C (Juliano value at 30°C cool down minus final viscosity at 95°C) 1996). Mean standard deviation of duplicate and setback (highest value at 30°C cool down minus

332 Molded Puffed Brown Rice Cakes

Table 1. Physicochemical properties of brown and milled rices used for brown-rice cakes. Brown Rice Milled Rice amylograph viscosity (BU) lnstron Variety or crude amylose alkali length Vlidth cooked rice Line Name . protein content spreading break- cons is- set- (mm) (mm) peak hardness a (%wb) (%db) value down Ieney back (kgJcnfl.__ IR65 6.8 2.0 12.3 2.2 7.0 485 135 10 -125 0.6±0.1 RD4 7.4 2.3 13.4 5.5 2.1 920 415 140 -275 0.8±0.1 PRJ5 4.7 2.7 9.2 11.7 7.0 685 330 165 -165 0.8±0.0 IR24 6.8 2.2 9.4 13.8 6.9 825 320 195 -125 09±0.0 Sinandomeng 6.8 2.0 9.4 12.7 6.0 815 415 170 -245 0.9±0.0 PSB Rc 12 6.9 2.1 11.4 20.8 7.0 595 175 325 150 1.5±0.1 PSB Rc 14 6.4 2.1 8.6 19.6 50 665 180 245 65 1.3±0.1 IR64 6.8 2.2 8.8 19.8 4.7 715 250 290 40 1.1±0.2 PSBRc6 6.3 2.1 11.3 22.0 7.0 630 70 505 435 17±0.1 PSBRc2 6.9 2.2 12.0 23.6 5.0 485 125 420 295 1.8±0.3 Mean 6.6 2.2 10.6 15.2 5.8 680 240 245 -5 11±0.1 ±SD 0.2 0.1 0.2 0.3 01 'Mean ± standard deviation. peak at 95°C) were calculated (Whalen et al. 1997). (Table 1 ). Cooked IR64 was softer than cooked PSB Rice cake flour was used in duplicate to check for Rc 12 among the intermediate-AC samples. residual gelatinization enthalpy using a Shimadzu RVA peak viscosity was highest for Sinandomeng DSC-50 differential scanning calorimeter (DSC} using and lowest for PSB Rc 2 (Table 2). Breakdown was 2 mg rice with 10 mL water in a low pressure cell at also highest for Sinandomeng. Consistency was a heating rate of 10°C/min from ambient temperature lowest for waxy rice and highest for intermediate-high­ to 100°C. AC rice types except for PSB Rc 2. Breakdown was also highest in intermediate-high-AC samples. RVA RESULTS AND DISCUSSION and Amylograph viscosity did not give identical curves probably because of the greater shear in the RVA. Raw rice properties Only PRJ 5 was short-grained since it is a Properties of rice cakes japonica type from the Philippines (Table 1). Protein Rice cakes were prepared from all. except for the content of brown rice was high in most samples two waxy rice types, IR65 and RD4, that burned and except for PSB Rc 14 and IR64. All AC-GT stuck on the mold at both specific volumes. Runs combinations were represented except high-GT, low­ with waxy rice at 19% water also burned, particularly AC rice. Amylograph viscosity showed highest peak IR65. Their cake would not hold together, in contrast viscosities for tow-AC rice types and high-GT waxy to nonwaxy cakes. Thus under the conditions of rice rice RD4 and lowest peak viscosity for low-GT waxy cake making, the presence of amylose seems IR65 and intermediate-GT, high-AC rice PSB Rc 2. important for proper puffing and adhesion of rice Breakdown was highest for low-AC rice types and cakes. RD4 and least for waxy IR65 and high-AC rice types. Brown rice cakes puffed at ,;;:>ecific volume of 11 Consistency and setback were lowest for waxy and mLig were slightly whiter (higher L* value) than those low-AC rice types and highest for high-AC rice types, at specific volume of 7 mUg probably because of the particularly the low-GT PSB Rc 6. lower density of the cakes. They, however, had similar lnstron cooked rice hardness at constant water­ a* (greenness) and b* (yellowness) values (Tables 3 rice ratio of 1.2 increased progressively with AC and 4). PSB Rc 2 cake was the least white and

333 B. 0. Juliano, L. T. Roferos and M Pels

Table 2. RVA viscosity of raw rices. RVA viscosity (RVU) Variety/Line Name ------Peak Breakdown Consistency Setback !R65 210 31 49 18 / RD4 256 110 13 -97 PRJ 5 249 117 124 7 !R24 240 85 187 102 Sinandomeng 294 141 154 13 PSB Rc 12 178 46 277. 231 PSB Rc 14 169 46 218 182 IR64 189 57 224 167 PSB Rc6 225 18 229 211 PSB Rc2 113 26 152 126 Mean 212 68 163 96 greenest at specific volume of 7 mUg and PSB Rc from work (area under the curve). PRJ 5 cake was 6, the least white at specific volume of 11 mL/g. Both harder than IR24 cake among the low-AC cakes. PSB Rc 2 and PSB Rc 6 were greenest at specific Among high-AC rice cakes, PSB Rc 6 was harder volume of 11 ml!g. whereas Sinandomeng cake was than PSB Rc 2. whitest and ieast yellow at both specific volumes. Similar mean three-point bending hardness values Huff eta!. (1992) obtained similar b* values but lower were observed for cakes at specific volumes of 7 and L* and a* values for rice cakes from US medium and 11 mUg, but PSB Rc 6 cake was harder for the long grain brown rice types. denser cake (7 mllg) (Tables 3 and 4). Higher !nstron hardness of the rice cake at spe:::ific puncture hardness values VJere observed at the lower volume of 7 mllg by a three-point bending system specific volume for IR24, PSB Rc 14, IR64 and PSB was highest for PSB Rc 14, followed by IR64 and Rc 2 cakes. On the other hand, PRJ 5 cake showed lowest for PRJ 5 (Table 3). PSB Rc 14 cake was the opposite effect. Highest hardness values were harder than PSB Rc 12 cake and high-AC and low­ observed for PSB Rc 14 cake at a specific volume of AC cakes. Using a modified puncture test (Hsieh et 7 ml/g (Table 3). Based on puncture work, IR24 and al. 1990), cakes at specific volume of 7 mUg were PSB Rc 14 cakes were harder at a specific volume evaluated. PSB Rc 14 cake was the hardest and PRJ of 7 mLig. Huff et al. (1992) also reported much more 5 cake was the softest for both peak and work (Table fragile cakes from US medium grain (low-GT, low-AC) 3}. Sinandomeng cake was as soft as PRJ 5 cake brown rice than from US long grain (intermediate-GT, based on work. PSB Rc 14 cake was also harder intermediate-AC) brown rice. than PSB Rc 12 cake and the high-AC and low-AC The performance of brown rice types within the cakes. The first peak force or crispness peak was not same AC-GT type was not always the same, observed, signifying that the cakes already had water particularly the three low-GT, low-AC rice types activity greater than 0.44 (Hsieh et al. 1990). (Tables 3 and 4). Among the intermediate-AC rice With cakes at specific volume of 11 mUg, !nstron types, low-GT PSB Rc 12 cake was softer than the three-point hardness was lowest for low-AC rice types two high-intermediate-GT r-akes, but IR64 cake was and highest in IR64 and PSB Rc 6 (Table 4). Among softer at 7 mlig. Among lh8 high-AC cakes, PSB Rc intermediate-AC cakes, PSB Rc 12 was softer than 6 (low GT) was softer than PSB Rc 2 (intermediate IR64. Among low-AC cakes, PRJ 5 was harder than GT) at a specific volume of 7 mLig, but the reverse IR24. With the puncture method, IR24 had the softest was true for cakes at a specific volume of 11 mlig. cake and PSB Rc 6, PSB Rc 14 and IR64 had the The viscosity profile of rice cakes using the RVA hardest cake (Table 3). Similar results were obtained (Whalen et al. 1997) reflected complete gelatinization

334 Molded Puffed Brown Rice Cakes

Table 3_ Properties of molded puffed-brown rice cakes with specific volume of 7 mUg_ Cake color fnstron hardness"' RVA viscosity' (RVU) Specific Variety or lnstron vo!ume work"' Cold 30"C nne name 3-poin1 Puncture Start at Break­ ConsiS­ Set (mUg) L• a• b. (kg.cm) bending (kglcm2) Start End 95"C dov;n tency back

IR65 73.9 7.0 15.0 17 14 5 0 2 2 RD4 70.C 73 lB.i 47 52 16 2 n 9 PRJ 5 7.7 72.1 63 14.2 2.5±0.1 0.69±0.01 5.3<0.7 50 30 11 6 10 4 IR24 7.4 72.9 6.3 13.0 2.8±().5 0.86::0.14 6.5±0.6 101 99 125 42 -28 -70 Sinar.domeng 7.0 73.1 6.1 12.9 2.7±04 0 73±0.14 53±1.1 SB 55 51 26 28 2 PSB Rc 12 6.9 72.0 6.0 13 5 3.3±0.6 0.87±0.07 6 6±0.3 48 43 43 18 27 9 PSB Rc 14 7.3 72.3 66 13.1 4.4±04 1.46±0.23 12.1±3.3 65 57 44 30 28 -2 IR64 69 72.6 65 13.2 4.0±0.6 1.18±0.10 8.1±1.5 59 43 28 16 18 2 PSB Rc 6 7.2 71.9 7.2 14.0 3.0±0.3 0.94±0.04 6.8±1 A 45 40 49 24 29 5 PSB Rc 2 7.0 70.0 6.5 13.9 3.3±0.2 1.14±0.06 7.6±1.2 50 46 60 37 44 7 Mean± SD 7.2 72.1 6.4 13.5 3.2±0.4 0.98±0.10 7.3±1.3 60 52 51 25 20 -5 ±1.2 ±0.2 +1.0 'Mean~ standard deviation 'No peak of 3o•c cold and 95"C heated paste. e:xcept peak at 56"C of cold RD4 cake

Cake color l:nstron hardness.a RVA viscosity" (RVU) Specific lnstron Variety or Cold 30"C volume worka line name 3-point Puncture Start Break- Consis- Set- !mUg) L• a• b. (kg.cm) bending {kg/cm2) Start End at 95"C down Ieney back

PRJ 5 113 73.0 6.3 138 2.9±0 1 086±0.15 7.8±1.9 51 4 2 0 29 29 IR24 10.6 75.2 6.4 13.4 2.5±0.2 0.55±0.13 4.6±0.9 49 9 4 0 6 6 Sinandomeng 10_9 758 59 11.5 2 7±0.4 0.68±0.15 6.1±11 55 49 15 6 21 15 PSB Rc 12 110 73.2 6.4 13.8 3.0±0.5 0.70±0.19 6.3±1.5 71 62 30 22 19 -3 PSB Rc 14 11' 1 74.4 6.4 12 9 3:6±0.5 0 93±0.20 9.4±2.3 59 20 13 3 12 9 IR64 11.9 75.5 6.4 12.4 4.0±0.4 0.90±0.12 9.0±1.9 75 12 12 7 11 4 PSB Rc 6 10_6 72.8 7.0 11 9 4.0±0.2 0 94±0.19 9.0± 1.6 72 57 56 43 52 9 PSB Rc 2 11.0 73.7 7.0 11.9 3.6±0.5 0.64±0.04 5.9±1.1 60 50 28 20 26 6 Mean± SD 10.9 74.7 6.5 12.7 3.3±0.4 0.78±0.15 7.3±1.5 62 33 20 10 22 9 +1.2 ±0.3 ±1.1 Mean± standard deviation 'No peak was observed for cold paste at 30"C and lor hot paste at 95"C_ and was similar to extrusion of cooked corn product PSB Rc 12 and PSB Rc 14 cakes at 11 mUg and (Whalen 1996) and pasted cooked rice and rice for PSB Rc 2, Sinandomeng and PRJ 5 cakes at 7 extrudate at 15% moisture (Whalen et aL 1997) with mL!g (data not shown). Hence, difference in degree no peak initially at 30°C and upon heating to 95°C of starch cooking was not a factor in differences in and little increase in viscosity on cooling at 30°C hardness and adhesion of the rice cakes. Hsieh et aL (Tables 3 and 4). The raw flour had much higher ( 1989) also reported complete starch gelatimzation of viscosity values (Table 2). Waxy IR65 had the lowest US long grain brown rice in puffed rice cake viscosity. IR24 had the lowest RVA pattern among the Simple correlation coefficients showed better nonwaxy rice cakes. Villareal & Juliano (1987) also correlation between the two hardness methods for reported a much reduced gel viscosity of gun-puffed cakes at specific volume of 7 mUg than for cakes at milled rice as compared with starting raw rice. The 11 mllg {Table 5). Puncture hardness and work were DSC thermograms of rice cakes confirmed that all highly correlated for both sets of cakes. Brown rice cake samples were essentially gelatinized by the dimensions and protein content were not significantly absence of endotherms in the GT range, except for correlated with cake hardness and work. Amylose

335 B. 0. Juliano, L. T. Roteros and M. Pels

Table 5. Simple correlation coefficients (r) between lnstron hardness of puffed brown rice cake and grain properties. r" with lnstron hardnesslwork at specific volume - - Puncture work Property 3-point bending Puncture (kg/cm2) (kg.cm) 7 mllg 11 ml/g 7 ml!g 11 mllg 7 ml/g 11 ml/g lnstron hardness Three-point bending 7 ml/g 1.00 0.62 **0.94 0.45 **0.92 0.57 Three-point bending 11 mllg 1.00 0.66 0.71 0.51 *0.76 Puncture {kg/cm2) 7 ml/g 1.00 0.39 **0.96 0.51 Puncture (kg/cm2) 11 mllg 1.00 0.43 **0.99 Puncture work (kg.cm) 7 ml/g 1.00 0.53 Brown rice length 0.37 0.11 0.34 -0.44 0.22 -0.33 Brown rice width -0.37 -0.17 -0.33 0.16 -0.29 0.08 Brown rice protein content -0.33 -0.22 -0.27 0.15 -0.17 -0.21

Milled rice amylose content 0.58 *0.77 0.63 0.22 0.48 0.30 Alkali spreading value *-0.74 -0.52 *-0.77 -0.19 -0.04 -0.32 Amylograph peak viscosity -0.26 -0.54 -0.36 -0.16 -0.24 -0.18 Amylograph breakdown viscosity -0.44 *-0.71 -0.50 -0.33 -0.41 -0.36 Amylograph consistency 0.19 *0.72 0.29 0.24 0.14 0.26 Amylograph setback.viscosity 0.32 *0.74 0.42 0.29 0.30 0.32 RVA peak viscosity -0.63 -0.55 *-0.71 -0.04 -0.58 -0.13 RVA breakdown viscosity -0.54 *-0.74 -0.62 -0.27 -0.52 -0.33 RVA consistency 0.52 0.35 0.34 0.23 0.36 0.27 RVA setback viscosity 0.62 0.60 0.56 0.29 0.52 0.35 lnstron cooked rice hardness 0.32 0.62 0.42 0.11 0.30 0.15

Cake RVA 7 or 11 ml/g Starting 30"C viscosity -0.03 *0.75 0.03 0.48 0.10 0.52 End 30"C viscosity -0.05 0.16 0.03 -0.15 0.09 -0.15 Starting 95"C viscosity -0.18 0.55 -0.05 0.25 -0.04 0.24 "Breakdown" viscosity 0.10 0.54 0.31 0.22 0.27 0.20 "Consistency" 0.32 0.39 0.33 0.40 0.23 0.32 "Setback" viscosity 0.22 -0.26 0.13 0.25 0.07 0.16 •correlations marh.ed by* are significant at 0.05 > P > 0.01 and those marked by** at P < 0.01. Unmarked values are not significant.

content only correlated with three-point bending 7 mL/g cakes correlated with raw-rice RVA peak hardness of 11 ml/g cakes, but alkali spreading value viscosity, but not in 11 mllg cakes. Thus, no rice correlated negatively with hardness by both methods property correlated consistently with hardness for only for 7 mUg cakes. Three-point bending hardness both sets of cakes. of 11 mUg cakes correlated with Amylograph Thus, intermediate-AC rice types with breakdown, consistency and setback, raw-rice RVA intermediate-high GT provides the best raw brown rice breakdown and rice-cake RVA starting viscosity at for molded cakes, although high-AC, low-GT brown 30°C, but not in 7 mllg cakes. Puncture hardness of rice was also satisfactory at high cake specific

336 Molded Puffed Brown Rice Cakes volume. Waxy rice types burned and failed to adhere Bean MM, Nishita KD, Blakeney AB, Welsh LA, together and expand, whereas the low-AC, low-GT Delgado LL, El Baya AW, Fossati G, Kongseree N, rice types were softer. The presence of intermediate Mendes FP, Brilhante S, Suzuki H, Tada AM & Webb to high AC was needed for optimum texture and BD. 1985. Cooperative study on amylography of integrity (grain adhesion) of the rice cake. Complete milled rice flour for pasting viscosity and starcn ge­ starch gelatinization was confirmed by both DSC and latinization temperature. Starch/Die Starke 37: 40- RVA analyses. 50. Follow-up pilot plant studies should be undertaken Juliano BO, Perez CM, Blakeney AB, Castillo DT, on more Philippine varieties to verify the above results. Kongseree N, Laignelet B, Lapis ET, Murty WS, Paule CM & Webb BD. 19b't. International coop­ Acknowledgment erative testing on the amylose content of milled rice. The authors wish to thank Tess Rola for manuscript Starch/Die Starke 33: 157-163. editing. Juliano BO & Sakurai J. 1985. Miscellaneous rice prod­ References ucts. In: Rice chemistry and technology, 2nd ed. Carpio EV, Gonzalez AM, Aco EV & Robles JS . 1990. (Ed BO Juliano) pp. 569-618. American Associa­ Survey and documentation of traditional food tion of Cereal Chemists, St Paul, MN (USA). processing equipment Project report to Philippine Juliano BO & Villareal CP 1993. Grain quality evalua­ Rice Research Institute, Maligaya, Munoz, Nueva tion of world rice types. International Rice Research Ecija. Institute of Food Science and Technology, Institute, Manila. University of the Philippines Los Banos, College, Little RR, Hilder GB & Dawson EH. 1958. Differential Laguna (Philippines). effect of dilute alkali on 25 varieties of milled white Davis CE. 1921. Shortening: its definition and meas­ rice. Cereal Chern. 35: 111-126. urement Indus. Eng. Chern. 13: 797-799. Roferos LT & Juliano BO. 1997. Chemometrics of grain Hsieh F, Hu L, Huff HE & Peng IC. 1990. Effects of quality of raw and cooked Philippine milled rice. Phil. water activity on textural characteristics of puffed Agriculturist 80:211-236. rice cake. Lebensmittei-Wissenschaft und­ USA Rice Council. 1992. Rice: consumer attitudes and Technologie 23: 471-473. consumption patterns. Houston, TX (USA). Hsieh F, Huff HE, Peng IC & Marek SW. 1989. Puffing Villareal CP & Juliano BO. 1987. Varietal differences in of rice cakes as influenced by tempering and heat­ quality characteristics of puffed rice types. Cereal ing conditions. J Food Sci. 54: 1310-1312. Chern. 64: 337-342. Huff HE, Hsieh F & Peng IC. 1992. Rice cake produc­ Whalen PJ. 1996. Fingerprinting cereal products in. tion using long-grain and medium-grain brown rice. Applications of the Rapid Visco Analyser (eds CE J Food Sci. 57: 1164-1167. Walker & JL Hazelton). Presented in part at the Juliano BO. 1996. Rice quality screening with the Rapid American Association of Cereal Ctlemists annual Visco Analyser. In: Applications of the Rapid Visco meetingfRVA symposium, 23-27 Oct 1994, Nash­ Analyser (eds CE Walker & JL Hazelton). Presented ville, TN (USA) pp 73-75. Newport Scientific Pty in part at American Association of Cereal Chem­ Ltd., Warriewood, NSW (Australia). ists annual meetingfRVA symposium, 23-27 Oct Whalen PJ, Bason ML, Booth Rl, Walker CE & 1994, Nashville, TN (USA) pp. 18-24. Newport Sci­ Williams PJ. 1997. Measurement of extrusion ef­ entific Pty Ltd, Warriewood, NSW (Australia). fects by viscosity profile using the Rapid Juliano BO, Perez CM, Alyoshin EP, Romanov VB, ViscoAnalyser. Cereal Foods World 42: 469-475.

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