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Three novel peptide sequences identified from palm kernel cake (PKC) generated protein hydrolysate including YLLLK, WAFS and GVQEGAGHYALL were used for stability study against angiotensin-converting enzyme (ACE), ACE-inhibition kinetics and molecular docking studies. Results showed that the peptides were degraded at different cleavage degrees of 94%, 67% and 97% for YLLLK, WAFS and GVQEGAGHYALL, respectively, after 3 h of incubation with ACE. YLLLK was found to be the least stable (decreased ACE-inhibitory activity) compared to WAFS and GVQEGAGHYALL (increased ACE-inhibitory activity). YLLLK showed the lowest Ki (1.51 mM) in inhibition kinetics study when compared to WAFS and GVQEGAGHYALL with Ki of 2 mM and 3.18 mM, respectively. In addition, ACE revealed the lowest Kmapp and Vmaxapp and higher catalytic efficiency (CE) in the presence of YLLLK at different concentrations, implying that the enzyme catalysis decreased and hence the inhibition mode increased. Furthermore, YLLLK showed the lowest docking score of −8.224 and seven interactions with tACE, while peptide GVQEGAGHYALL showed the higher docking score of −7.006 and five interactions with tACE.

This study analyzed the volatile organic compounds (VOCs) of three mango varieties (Harumanis, Tong Dam and Susu) for the discrimination of authentic Harumanis from other mangoes. The VOCs of these mangoes were extracted and analysed nondestructively using Head Space-Solid Phase Micro Extraction (HS-SPME) coupled to Gas Chromatography-Mass Spectrometry (GC-MS). Prior to the analytical method, two simple sensory analyses were carried out to assess the ability of the consumers to differentiate between the Harumanis and Tong Dam mangoes as well as their preferences towards these mangoes. On the other hand, chemometrics techniques, such as principal components analysis (PCA), hierarchical clustering analysis (HCA), and discriminant analysis (DA), were used to visualise grouping tendencies of the volatile compounds detected. These techniques were successful in identifying the grouping tendencies of the mango samples according to the presence of their respective volatile compounds, thus enabling the identification of the groups of substances responsible for the discrimination between the authentic and unauthentic Harumanis mangoes. In addition, three ocimene compounds, namely beta-ocimene, trans beta-ocimene, and allo-ocimene, can be considered as chemical markers of the Harumanis mango, as these compounds exist in all Harumanis mango, regardless the different sources of the mangoes obtained.

Methanol and isopropanol were used as extraction solvent to determine the percentage yield of chlorogenic acid (CGA) in green Robusta (Coffea canephora) coffee bean. CGA was extracted by using isolation method with activated carbon to trap the CGA content from the complex compounds in green coffee beans. Results indicated that percentage yield of CGA extracted by using isopropanol was significantly higher (5.21%) compared to methanol (4.55%). Besides, antioxidant activity and total phenolic content were also analyzed. From this study, isopropanol extracted more antioxidant activity and total phenolic content as compared to methanol. For antioxidant activity, isopropanol and methanol extracted 0.48 mg and 0.15 mg of Fe (II) per gram of dry sample, respectively. For total phenolic content, isopropanol and methanol extracted 30.65 mg and 16.26 mg of gallic acid per gram of dry sample, respectively. Isopropanol extraction with ratio 60:40 (isopropanol: water) conserved more CGA content than methanol which was analyzed using high performance liquid chromatography. Chromatogram showed that the retention time of CGA is at 4.68 minutes which is similar to the retention time of standard CGA.Keywords: green coffee bean, antioxidant, phenolic, methanol, isopropanol Abstrak Metanol dan isopropanol telah digunakan sebagai pelarut ekstrak untuk menentukan peratusan hasil asid klorogenik (CGA) di dalam biji kopi hijau Robusta (Coffea canephora). CGA diekstrak dengan menggunakan kaedah pengasingan dengan karbon teraktif berfungsi sebagai perangkap kandungan CGA daripada sebatian kompleks di dalam biji kopi hijau. Keputusan hasil peratusan CGA yang diekstrak oleh isopropanol adalah secara signifikan lebih tinggi (5.21%) berbanding metanol (4.55%). Selain itu, aktiviti antioksidan dan jumlah kandungan fenolik juga telah dianalisis. Daripada kajian ini, pelarut isopropanol mengekstrak lebih banyak aktiviti antioksidan dan jumlah kandungan fenolik berbanding pelarut metanol. Bagi penentuan aktiviti antioksidan isopropanol dan metanol berupaya mengekstrak masing -masing 0.48 mg dan 0.15 mg Fe (II) bagi setiap gram sampel kering. Bagi penentuan jumlah kandungan fenolik, isopropanol dan metanol mengekstrak 30.65 mg dan 16.26 mg asid gallic bagi setiap gram sampel kering. Pengekstrakan isopropanol dengan nisbah 60:40 (isopropanol: air) memelihara lebih kandungan CGA daripada metanol yang dianalisa menggunakan kromatografi cecair prestasi tinggi. Kromatogram menunjukkan bahawa masa tahanan CGA adalah pada 4.68 minit selari dengan masa tahanan larutan piawai CGA.Kata kunci: biji kopi hijau, antioksidan, fenolik, metanol, isopropanol

An edible lipid-chitosan film forming dispersion (FFD) was developed to delay ripening of guava. Four percent (v/v) of palm stearin (PS) and palm kernel olein (PKOo) in ratios of 0:100, 25:75, 50:50, 75:25 and 100:0 were added to a chitosan solution base and applied on guava by dipping technique. Surface appearance, weight loss, firmness, carbon dioxide, oxygen and ethylene concentrations were evaluated every 3 days during 31 days of storage at chilled temperature (5±2 °C). An application of FFD on guava significantly (p <0.05) delayed chilling injury, reduced weight loss, maintained firmness, slowed down respiration and ethylene production as compared to uncoated guavas. PS:PKOo (75:25) coating was able to form compatible blends and showed good moisture and gas barrier properties when applied on guava surface, resulting in increased postharvest life of guava.Keywords: guava, film forming dispersion, chitosan, palm stearin, palm kernel olein Abstrak Serakan filem lipid-kitosan yang boleh dimakan telah dihasilkan untuk melambatkan proses jambu untuk ranum. Empat peratus (v/v) stearin sawit dan olein isirong sawit dengan nisbah 0:100, 25:75, 50:50, 75:25 and 100:0 telah ditambah ke dalam larutan kitosan dan diaplikasikan ke atas jambu dengan menggunakan teknik celupan. Permukaan buah, kehilangan berat, kekerasan, kepekatan gas karbon dioksida, oksigen dan etilena telah dikaji setiap 3 hari sepanjang 31 hari penyimpanan di dalam suhu sejuk (5±2 °C). Penggunaan salutan ke atas jambu telah melambatkan kerosakan buah, mengurangkan kehilangan berat, mengekalkan kekerasan, melambatkan proses respirasi dan penghasilan etilena jika dibandigkan dengan jambu yang tidak disalut. Salutan PS:PKOo (75:25) telah menghasilkan campuran yang sesuai dan menunjukkan sifat-sifat penghalang air dan gas yang baik apabila diaplikasikan ke atas permukaan jambu dan telah meningkatkan jangka hayat jambu.Kata kunci: jambu, serakan lapisan filem, kitosan, stearin sawit, olein isirong sawit IntroductionGuava is an excellent source of vitamin C and is grown for both the domestic and exports markets. However, guava ripens rapidly during transportation and storage, thus often requiring rapid shipment in order to prolong postharvest life and decrease its respiration rate. Many postharvest diseases such as anthracnose, mucor rot and aspergillus rot can also limit the commercialisation of guava. Although refrigeration can increase the shelf life of guava, it adds cost and may cause chilling injury. Thus, coating the fresh fruit appears to be a cheaper alternative to preserve guava.