Texture Profile of Lamtoro Gung Tempeh

Dr Isabella Nyambayo, Senior Lecturer in Nutrition and Metabolism, and colleagues have recently published a paper investigating the properties of Lamtoro Tempeh using different packaging.  

Lamtoro Gung is a Fabaceae family plant originating from Southern Mexico and Central America, thriving in tropical and subtropical climates. Its seeds, rich in protein (31-46%) and low in fat (5.1-10%), are consumed in regions like Central America, Thailand, and Indonesia. These seeds contain negatively charged polar amino acids, potentially making them a source of ACE-I peptides, which help prevent hypertension, with their antihypertensive properties enhanced through germination. 

Lamtoro Gung seeds are often used to make tempeh, a traditional fermented product. This study explores how different packaging materials—plastic, banana leaves, and teak leaves—and fermentation durations affect the texture of Lamtoro Gung tempeh. 

Methods 

The study utilized scales, plastic bowls, steamers, and an Ametek Brookfield CTX texture analyzer. Key materials included Lamtoro Gung seeds from Wonogiri, teak leaves from Deresan Village, Bantul, banana leaves from Bantul Market, yeast (Padi brand, Indonesia), PE plastic, cassava flour, and distilled water. 

Preparation of Lamtoro Gung Seeds: 

1. Washing and Boiling: Seeds were washed and boiled in a 1:3 seed-to-water ratio for an hour.
2. Cleaning: Skins were removed, and seeds were washed repeatedly.
3. Soaking: Seeds were steeped in water for 24 hours, with water changed every 8 hours.
4. Mixing with Cassava Flour: After soaking, seeds were mixed with 25 g of cassava flour, cooked for an hour, and cooled.

Making Lamtoro Gung Seed Tempeh: 

1. Yeast Addition: 1 g of yeast was added to the cooled seeds.
2. Packaging: 30 g of yeast-treated seeds were wrapped in teak leaves, banana leaves, or PE plastic.
3. Fermentation: Wrapped seeds were fermented for 24, 48, 72, and 96 hours at 25-30°C in an incubator.

The study involved three packaging types (teak leaves, banana leaves, plastic) and four fermentation durations, with each sample repeated three times. Texture testing was performed using the Ametek Brookfield CTX texture analyzer, measuring hardness, cohesiveness, adhesiveness, gumminess, chewiness, and springiness.  

Results 

The texture profile of Lamtoro Gung tempeh includes six attributes: hardness, cohesiveness, adhesiveness, gumminess, chewiness, and springiness. 

Hardness: Measured as the maximum force during the first bite in Newtons (N). No significant difference in hardness was found between tempeh wrapped in different materials across most fermentation days. However, on the fourth day, tempeh in teak leaves showed the highest hardness due to dense mycelial growth forming a compact mass. 

Cohesiveness: Indicates the strength of internal bonds. The highest cohesiveness was observed in tempeh fermented in teak leaves on the third and fourth days and in plastic on the fourth day. This is linked to the mycelial growth in larger spaces provided by teak and banana leaves compared to plastic. 

Adhesiveness: The negative force area during the first bite, reflecting the effort needed to overcome attraction forces. The highest adhesiveness was observed in tempeh wrapped in banana leaves on the third day, due to better air circulation from the pores in banana and teak leaves enhancing fungal growth. 

Gumminess: Combining hardness and cohesiveness, the highest gumminess was found in tempeh fermented in teak leaves on the fourth day. This property is crucial for semi-solid foods like tempeh. 

Chewiness: Refers to the energy needed to masticate solid foods, calculated as gumminess × springiness. Higher chewiness indicates a denser product. 

Springiness: Measures the sample's elasticity. The control sample (day 0) had the highest springiness, with no significant changes across other samples. 

Conclusion 

Lamtoro Gung tempeh can be a viable alternative to soybean tempeh. Packaging with teak leaves for four days of fermentation produced the best texture, with high scores in hardness, cohesiveness, gumminess, and chewiness. This study underscores the importance of packaging material and fermentation duration in achieving desired textural qualities in tempeh production. 

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